eye

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. An organ of vision or of light sensitivity.
2. n. Either of a pair of hollow structures located in bony sockets of the skull, functioning together or independently, each having a lens capable of focusing incident light on an internal photosensitive retina from which nerve impulses are sent to the brain; the vertebrate organ of vision.
3. n. The external, visible portion of this organ together with its associated structures, especially the eyelids, eyelashes, and eyebrows.
4. n. The pigmented iris of this organ.
5. n. The faculty of seeing; vision.
6. n. The ability to make intellectual or aesthetic judgments: has a good eye for understated fashion.
7. n. A way of regarding something; a point of view: To my eye, the decorations are excellent.
8. n. Attention: The lavish window display immediately got my eye.
9. n. Watchful attention or supervision: always under his boss's eye; kept an eye on her valuables.
10. n. Something suggestive of the vertebrate organ of vision, especially:
11. n. An opening in a needle.
12. n. The aperture of a camera.
13. n. A loop, as of metal, rope, or thread.
14. n. A circular marking on a peacock's feather.
15. n. Chiefly Southern U.S. The round flat cover over the hole on the top of a wood-burning stove. Also called regionally cap¹, griddle.
16. n. A photosensitive device, such as a photoelectric cell.
17. n. Botany A bud on a twig or tuber: the eye of a potato.
18. n. Botany The often differently colored center of the corolla of some flowers.
19. n. Meteorology The circular area of relative calm at the center of a cyclone.
20. n. The center or focal point of attention or action: right in the eye of the controversy.
21. n. Informal A detective, especially a private investigator.
22. n. A choice center cut of meat, as of beef: eye of the round.
23. v. To look at: eyed the passing crowd with indifference.
24. v. To watch closely: eyed the shark's movements.
25. v. To supply with an eye.
26. idiom. all eyes Fully attentive.
27. idiom. an eye for an eye Punishment in which an offender suffers what the victim has suffered.
28. idiom. clap To look at.
29. idiom. eye to eye In agreement: We're eye to eye on all the vital issues.
30. idiom. have eyes for To be interested in.
31. idiom. have (one's) eye on To look at, especially attentively or continuously.
32. idiom. have (one's) eye on To have as one's objective.
33. idiom. in the eye of the wind Nautical In a direction opposite that of the wind; close to the wind.
34. idiom. in the public eye Frequently seen in public or in the media.
35. idiom. in the public eye Widely publicized; well-known.
36. idiom. my eye Slang In no way; not at all. Used interjectionally.
37. idiom. with an eye to With a view to: redecorated the room with an eye to its future use as a nursery.
38. idiom. with (one's) eyes closed Unaware of the risks involved.
39. idiom. with (one's) eyes open Aware of the risks involved.

Century Dictionary and Cyclopedia

1. n. The organ of vision; the physiological mechanism of the sense of sight; an anatomical arrangement of parts by which optical images may be formed; in general, any part of an animal body by means of which the faculty of vision is exercised, or the impact of the light-rays is sensed as a visual impression or optical image. In most of the higher animals, as nearly all vertebrates, the eye is developed as a very special sense-organ of great structural complexity and functional delicacy. But from the point of view of comparative anatomy an eye is any part of an animal body which responds more readily than other parts to the special stimulus of light, or whose activity is specially excited by the impact of light-rays. Thus, an extremely rude eye in the form of a mere spot, often a pigment-spot sensitive*** light, is common in low animals, as in infusorians, a*** may be situated anywhere on the body, and may be indefinitely multiplied in number. These rudiments of eyes are commonly described as eye-specks, eye-points, or eye-spots. (See cut under Balanoglossus.) In various cœlenterates and echinoderms organs apparently responsive to the action of light occur in various parts of the body and in varying numbers. Somewhat higher in the scale of evolution, eyes become unmistakable in structural character, however dim or uncertain their actual visual function may be, as in worms, snails, etc. But in some of the Mollusca, as cuttlefishes, eyes are highly specialized as visual organs of conspicuous character, comparable to those of vertebrates, though constructed on a different plan. In the vast assemblage of arthropods, as crustaceans, insects proper, and arachnidans, constituting a large majority of the animal kingdom, eyes as a rule are well developed under one or both of two main modifications, namely, the simple eye or ocellus and the compound eye or oculus. (See compound eye, below, and cut under falx.) Such eyes are usually only two, but may be four, six, or eight in number. These higher numbers of eyes occur chiefly in arachuidans, as spiders. Crustaceans have normally a single pair, often mounted on movable eye-stalks or ophthalmites, which are modified limbs of one of the cephalic segments. (See cut under stalk-eyed.) A few crustaceans have a single median eye. In vertebrates, where the eyes are normally never more nor fewer than one pair, these organs are received in special formations of the skull, the sockets or orbits of the eyes; and the eyes are usually further defended from accidental injury by various contrivances, as eyelids, eyelashes, and eyebrows. (See these words.) Other appendages of the eye namable among its “defenses” are the lacrymal apparatus, which secretes tears to moisten the organ, and the glandular structures (Meibomian follicles), which serve for its lubrication by secreting a greasy substance. The front of the eye has usually a special mucous membrane, the conjunctiva. The most essential or intimate parts of the organ of vision are contained in a globe or disk, the eyeball (which see), which is freely movable in its socket in the higher vertebrates, and rolled about by the action of various muscles, as the four recti and two obliqui of man and the choanoid muscle of some mammals. Externally the eyeball consists for the most part of a tough opaque membrane, the sclerotic; but in front, of a hard transparent structure, the cornea. These together are the outermost of three tunics or coats of the eye; the second tunic consists of the choroid coat and ciliary processes and the iris, and the third and innermost of the retina, the expanded end of the optic nerve, which enters the ball from behind and spreads out upon the choroid to a varying extent. The retina receives optical impressions focused upon it by the crystalline lens, which are transmitted by the optic nerve to the brain, where they are sensed as visual images. The hollow eyeball with its several tunics forms a kind of camera filled with certain solid and fluid refractive media. Directly in the axis of vision in the interior of the ball is suspended a solid biconvex body, the crystalline lens, serving to bring rays of light to a focus on the retina. The lens, inclosed in its capsule, also divides the interior of the eye into two compartments. The larger rear compartment is filled with a glassy fluid, the vitreous humor, inclosed in a delicate hyaloid membrane, which may also send prolongations through its substance. In front of the lens, between this structure and the cornea, the space is filled with a more watery fluid, the aqueous humor. This anterior space is partly divided into an anterior and a posterior chamber by the iris, which hangs in front of the lens like a curtain with a hole in the middle, the pupil. Besides the optic nerve, or special nerve of sight, the eye is supplied with other motor, sensory, and sympathetic nerves, and has its appropriate blood-vessels. In man both eyes look directly forward, their axes being parallel, though the orbits in which they are contained present a little outward, or away from each other. The optic nerve follows the axis of the orbit, and consequently pierces the eyeball behind, a little on the inner side—that is, toward the nose. The muscles which move the ball are six, the rectus superior, rectus inferior, rectus externus, rectus internus, obliquus superior, and obliquus inferior. These muscles are innervated by three motor nerves, the oculomotor, trochlear or pathetic (distributed to the obliquus superior), and abducent (distributed to the rectus externus). The ball is embedded in a quantity of adipose tissue forming a soft cushion, but is also somewhat isolated by means of a thin membranous sac called the vaginal tunic or sheath of the eye. The ball is nearly spherical or globular, but is a little deeper and wider across than from before backward, measuring about an inch in each of the former axes and of an inch in the latter. (For the structure of the several tunics, see sclerotic, cornea, choroid, ciliary, iris, and retina.) The retina is an expansion of the optic nerve into a large, circular, concavo-convex sheet, which rests upon the choroid with its inner surface in contact with the body of vitreous humor in the back of the eye. In the middle of it and in the axis of the eye is a little rounded elevation, the yellow spot, or macula lutea, with a depression at its summit, the fovea centralis. To the nasal side of the yellow spot is the entrance of the optic nerve and of the central retinal artery; and here the retina lacks the visual function which characterizes all the rest of its surface. The lens is suspended in a transparent capsule in the axis of vision; it is biconvex, and more convex on its posterior than on its anterior surface. It is about ⅓ of an inch across and ¼ of an inch deep, and its structure presents concentric laminations. It tends to fiatten with age. (See crystalline lens, under crystalline.) The vitreous humor fills the hollow of the eyeball behind the lens. It is a glassy or jelly-like substance, consisting chiefly of water, with a little saline and albuminous material, inclosed in a delicate hyaloid membrane continuous in front with the capsule and suspensory ligament of the lens, and behind resting upon the retina. Some prolongations of the hyaloid enter the substance of this humor, and one of these is called the canal of Stilling. The quantity of vitreous humor, or bulk of the vitreous body, is about ⅘ of the entire mass of the eyeball. The aqueous humor is the slightly saline watery fluid which fills the eye in front of the lens, between this and the cornea, on both sides of the iris, consequently occupying the whole of the anterior and posterior chambers of the eye. Its bulk is very small. (See conjunctiva, lacrymal, Meibomian, nasal, ocular, ophthalmic, optic, palpebral, superciliary, tarsal, etc.) The eye agrees with other sense-organs in development in the embryo, in being partly formed by the inversion or involution of a portion of epiblast from without, and partly by protrusion or evolution from within of a primitive ocular vesicle, the two coming together in the situation where the lens is to be developed. The result is that a portion of epiblast from the back of the embryo, which had been shut into the hollow of the cerebrospinal tube, pushes out from one of the cerebral vesicles to meet another portion of epiblast from the face of the embryo. Thus, the retina and associate parts are an outgrowth from the undeveloped brain, while the lens and associate epithelial structures are an ingrowth of epidermis. In other mammals with well-formed eyes the structure is substantially the same as in man, though minor and incidental variations are numerous. The eyes of quadrupeds usually present laterally, and not directly forward. They are usually relatively larger and probably much more effective organs of vision than those of man. They frequently develop a special choanoid muscle or retractor of the eyeball. The iris is commonly black, brown, or of some dark tint, seldom bluish or pale. It often contracts in such a way that the pupil is linear, elliptical, or narrowly oval, instead of circular, as in man. This is well seen in the cat. In birds several modifications occur. The eyeball is strengthened and its shape molded by a set of splint-bones or small bony plates disposed in a circle in the sclerotic around the cornea. The ball is hemispherical with an anterior projection, somewhat like a short acorn in a large cup, and the cornea is very convex. The pupil is always circular, though the iris may be so motile as to present only a narrow ring round the pupil, or to reduce the pupil to a mere point. These changes are well seen in the eyes of owls. There is also in the vitreous humor a peculiar plaiting or folding of the choroid, called the marsupium or pecten. The visual range and power of the eye in some birds, if not in all, are much greater than in man. All birds have three eyelids, the third very fully developed and arranged so as to sweep entirely across the front of the eye by means of special muscles and tendons upon the back of the eyeball. No birds are eyeless. In reptiles the eyes are structurally more like those of birds than of mammals. Some reptiles are eyeless, or have very rudimentary eyes. Most have eyelids, but these are wanting in ophidians, a transparent cuticle being continued directly over the ball, and shed with the rest of the cuticle. In fishes the eyes are generally symmetrically lateral, but not infrequently dorsal and closely approximated to each other, and rarely inferior; in one type, the heterosomes or flat-fishes, they are, however, both on one side, that belonging to the side which rests on the ground being in the very young in the normal position, but soon actually penetrating through the integument, and with the circumocular cranial region twisting to the opposite side and assuming a permanent position above the regular eye of the colored or uppermost side. The accessories of the eyes of mammals are undeveloped in fishes, but the eyes themselves are sometimes covered by a fold of the integument, and sometimes, as in some sharks, by a peculiar nictitant membrane. Among the most characteristic features are the flattening of the cornea and the sphericity of the crystalline lens. In one group (Anableps) a remarkable deviation from all other forms occurs, in that the cornea is divided by a horizontal band of the conjunctiva into upper and lower halves, and two pupils are developed, the species consequently being known as four-eyed fishes. In the lowest of the vertebrates (Branchiostoma) the eye is represented by a very small spot, coated with dark pigment and receiving the end of a short nerve. See vision.
2. n. In a restricted or specific use, some part or appurtenance of the physical eye, taken as representing the whole. The hole in the iris through which light enters; the pupil: as, owls' eyes contract in daylight; circular or oval eyes.
3. n. Figuratively Vision; the act of seeing, or the field of sight; hence, observation; watch.
4. n. The power of seeing; range or delicacy of vision; appreciative or discriminative visual perception: as, to have the eye of a sailor; he has an eye for color, the picturesque, etc.
5. n. Mental view or perception; power of mental perception; opinion formed by observation or contemplation.
6. n. Look; countenance; aspect; face; presence.
7. n. Regard; respect; view; close attention; aim.
8. n. Opposed aspect or course; confronting presentation or direction: chiefly or wholly nautical: as, to steer a ship in the sun's eye; to sail in the wind's eye.
9. n. Something resembling or suggesting an eye in shape, position, or general appearance. Specifically— The bud or shoot of a plant or tuber.
10. n. One of the spots on a peacock's tail.
11. n. The muscular impression on the inner side of the shell of a bivalve, as an oyster. See ciborium.
12. n. The hole or aperture in a needle through which the thread passes.
13. n. The hole in any instrument or tool in which a handle or the like is secured, or through which it is passed, as that for the handle in a hammer-head, that for the helve in an ax, that for the ring in the shank of an anchor, etc.
14. n. The hole of a millstone through which the grain passes.
15. n. In metallurgy, an opening at the angle of the tuyere, or where the tuyere connects with the gooseneck, in a blast-furnace, through which the state of the interior may be examined. This opening, which is protected by a plate of glass or mica, is called the eye of the furnace.
16. n. The catch of bent wire into which a hook (forming with it a hook and eye) is inserted.
17. n. An eyebolt.
18. n. Nautical, the loop at the upper end of a backstay or pair of shrouds which goes over the masthead of a ship.
19. n. The metal loop at the end of a harness-trace.
20. n. In archery, the loop of a bowstring which passes over the upper nock in bracing.
21. n. The socket at the end of a carriage-pole or shaft.
22. n. The center of a wheel or crank, designed to receive the shaft or axle.
23. n. The center of a target.
24. n. In architecture, a general term for the distinctly marked center of anything: thus, the eye of a volute is the circle at its center from which the spiral lines spring; the eye of a dome is a circular aperture at its apex; the eye of a pediment is a circular window in its center.
25. n. A center or focus of light, power, or influence: as, the sun is the eye of day.
26. n. A slight or just distinguishable tint of a color; tinge; shade.
27. n. In Crustacea, a calcareous concretion embedded in the walls of the stomach. These concretions are supposed, but not known, to furnish a supply of calcareous substance for the formation of the new-shell after a molt; but they are so small that this theory is hardly tenable. In the case of the higher crustaceans they are more fully called crab's eyes. (See crab.) In the crawfish they are two discoidal plates in the middle of the lateral surface of the walls of the anterior dilated portion of the cardiac division of the stomach, and weigh about two grains. They begin as calcareous deposits underneath the chitinous gastric lining, and increase until the creature molts, when they are also shed, together with the lining membrane and gastric armature.
28. n. An eye whose lids and surrounding parts are livid or discolored, as by a blow or bruise.
29. n. Figuratively, defeat; repulse; injury; disgrace or disfavor; hence, a shock, as if from a blow on the eye: as, that scheme got a black eye in the committee; I will give him a black eye in print.
30. n. To take the conceit out of a person; show one how foolish one is: as, to wipe one's eye for him.
31. To fix the eye on; look at; view; observe; particularly, to observe or watch narrowly or with fixed attention.
32. To make an eye in: as, to eye a needle.
33. To be seen; appear; have an appearance.
34. n. A brood: as, an eye or a shoal of fish.
35. n. In some echinoids, a minute pigmented nodule, probably without visual functions, situated at the end of an ambulacrum.
36. n. In photography, the spectral range of wave-lengths to which a photographic plate or film is sensitive
37. n. In chitons, one of the numerous pigmented spots scattered either irregularly or symmetrically over the outer surface of the exposed area of the shell. “Same as shell-eye.

Wiktionary

1. n. An organ that is sensitive to light, which it converts to electrical signals passed to the brain, by which means animals see.
2. n. The visual sense.
3. n. Attention, notice.
4. n. The ability to notice what others might miss.
5. n. A meaningful stare or look.
6. n. A private eye: a privately hired detective or investigator.
7. n. A hole at the blunt end of a needle through which thread is passed.
8. n. A fitting consisting of a loop of metal or other material, suitable for receiving a hook or the passage of a cord or line.
9. n. The relatively clear and calm center of a hurricane or other such storm.
10. n. A mark on an animal, such as a peacock or butterfly, resembling a human eye.
11. n. The dark spot on a black-eyed pea.
12. n. A reproductive bud in a potato.
13. n. informal The dark brown center of a black-eyed Susan flower.
14. v. To observe carefully.
15. v. To view something narrowly, as a document or a phrase in a document.
16. v. To look at someone or something as if with the intent to do something with that person or thing.
17. v. obsolete To appear; to look.

GNU Webster's 1913

1. n. (Zoöl.) A brood.
2. n. The organ of sight or vision. In man, and the vertebrates generally, it is properly the movable ball or globe in the orbit, but the term often includes the adjacent parts. In most invertebrates the eyes are immovable ocelli, or compound eyes made up of numerous ocelli. See ocellus.
3. n. The faculty of seeing; power or range of vision; hence, judgment or taste in the use of the eye, and in judging of objects
4. n. The action of the organ of sight; sight, look; view; ocular knowledge; judgment; opinion.
5. n. The space commanded by the organ of sight; scope of vision; hence, face; front; the presence of an object which is directly opposed or confronted; immediate presence.
6. n. Observation; oversight; watch; inspection; notice; attention; regard.
7. n. That which resembles the organ of sight, in form, position, or appearance.
8. n. (Zoöl.) The spots on a feather, as of peacock.
9. n. The scar to which the adductor muscle is attached in oysters and other bivalve shells; also, the adductor muscle itself, esp. when used as food, as in the scallop.
10. n. The bud or sprout of a plant or tuber.
11. n. The center of a target; the bull's-eye.
12. n. A small loop to receive a hook.
13. n. The hole through the head of a needle.
14. n. A loop forming part of anything, or a hole through anything, to receive a rope, hook, pin, shaft, etc..
15. n. The hole through the upper millstone.
16. n. That which resembles the eye in relative importance or beauty.
17. n. obsolete Tinge; shade of color.
18. v. To fix the eye on; to stare at; to look on; to view; to observe; particularly, to observe or watch narrowly, or with fixed attention; to hold in view.
19. v. obsolete To appear; to look.

WordNet 3.0

1. n. a small hole or loop (as in a needle)
2. n. attention to what is seen
3. n. the organ of sight
4. n. an area that is approximately central within some larger region
5. v. look at
6. n. good discernment (either visually or as if visually)