medium

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Something, such as an intermediate course of action, that occupies a position or represents a condition midway between extremes.
2. n. An intervening substance through which something else is transmitted or carried on.
3. n. An agency by which something is accomplished, conveyed, or transferred: The train was the usual medium of transportation in those days.
4. n. Usage Problem A means of mass communication, such as newpapers, magazines, radio, or television.
5. n. Usage Problem The group of journalists and others who constitute the communications industry and profession.
6. n. Computer Science An object or device, such as a disk, on which data is stored.
7. n. A person thought to have the power to communicate with the spirits of the dead or with agents of another world or dimension. Also called psychic.
8. n. A surrounding environment in which something functions and thrives.
9. n. The substance in which a specific organism lives and thrives.
10. n. A culture medium.
11. n. A specific kind of artistic technique or means of expression as determined by the materials used or the creative methods involved: the medium of lithography.
12. n. The materials used in a specific artistic technique: oils as a medium.
13. n. A solvent with which paint is thinned to the proper consistency.
14. n. Chemistry A filtering substance, such as filter paper.
15. n. A size of paper, usually 18 × 23 inches or 17 ¹/₂ × 22 inches.
16. adj. Occurring or being between two degrees, amounts, or quantities; intermediate: broil a medium steak. See Synonyms at average.

Century Dictionary and Cyclopedia

1. n. That which holds a middle place or position; that which comes or stands between the extremes in a series, as of things, principles, ideas, circumstances, etc.; a mean.
2. n. Technically— In mathematics, a mean. See mean.
3. n. In logic, the mean or middle term of a syllogism.
4. n. A size of paper between demy and royal. American printing-medium is 19 × 24 inches; American writing-medium, 18 × 23 inches; English printing-medium, 18 × 28 inches; English writing-medium, 17½ × 22 inches; American double medium, 24 × 38 inches; and American medium and a half, 24 × 30 inches.
5. n. Anything which serves or acts intermediately; something by means of which an action is performed or an effect produced; an intervening agency or instrumentality: as, the atmosphere is a medium of sound.
6. n. Specifically— In painting, any liquid vehicle, as linseed-oil, poppy-oil, varnish, or water, with which dry pigments are ground, or with which pigments are mixed by the painter while at work, in order to give them greater fluidity.
7. n. In acoustics, a ponderable elastic substance, as air or other gas, water, etc., which transmits the energy of the sounding body in waves of condensation and rarefaction to the ear.
8. n. In heat and light, that which transmits the energy of the heated or luminous body to a distance in undulatory waves; the ether.
9. n. In bacteriology, the nutritive substance, either a liquid or a solid, in which or upon which the various forms of microscopic life are grown for study. The liquid media employed are infusions of hay, extract of beer-yeast, and broth of various kinds of meat. The solid media most used are eggs, slices of potatoes and carrots, agar-agar, and especially gelatin and the gelatinized serum of the blood of oxen. After being thoroughly sterilized by heat, they are usually placed in test-tubes, and inoculated with the form that it is desired to study; the cultures may then be observed through the glass.
10. n. A person through whom, or through whose agency, another acts; specifically, one who is supposed to be controlled in speech and action by the will of another person or a disembodied being, as in animal magnetism and spiritualism; an instrument for the manifestation of another personality. Many of the so-called spiritual mediums claim the power of acting upon and through matter, by means of the spirits controlling them, in a manner independent of ordinary material conditions and limitations. In this sense the plural mediums is preferred.
11. n. Something of mean or medium weight, size, etc.
12. Middle; middling; mean: as, a man of medium size. Synonyms See mean, n.

Wiktionary

1. n. The nature of the surrounding environment, e.g. solid, liquid, gas, vacuum, or a specific substance such as a solvent.
2. n. The material or empty space through which signals, waves or forces pass.
3. n. A format for communicating or presenting information.
4. n. engineering The materials used to finish a workpiece using a mass finishing or abrasive blasting process.
5. n. microbiology A nutrient solution for the growth of cells in vitro.
6. n. The means or channel by which an aim is achieved.
7. n. A liquid base which carries pigment in paint.
8. n. painting A tool used for painting or drawing.
9. n. spiritualism Someone who supposedly conveys information from the spirit world.
10. n. Anything having a measurement intermediate between extremes, such as a garment or container.
11. n. A person whom garments or apparel of intermediate size fit.
12. n. Ireland, dated, informal A half-pint serving of Guinness (or other stout in some regions).
13. adj. obsolete Arithmetically average.
14. adj. Of intermediate size, degree, amount etc.
15. adj. Of meat, cooked to a point greater than rare but less than well done; typically, so the meat is still red in the centre.

GNU Webster's 1913

1. n. That which lies in the middle, or between other things; intervening body or quantity.
2. n. Middle place or degree; mean.
3. n. (Math.) See Mean.
4. n. (Logic) The mean or middle term of a syllogism; that by which the extremes are brought into connection.
5. n. A substance through which an effect is transmitted from one thing to another. in animal magnetism, spiritualism, etc., a person through whom the action of another being is said to be manifested and transmitted.
6. n. rare An average.
7. n. A trade name for printing and writing paper of certain sizes. See Paper.
8. n. (Paint.) The liquid vehicle with which dry colors are ground and prepared for application.
9. n. (Microbiology) A source of nutrients in which a microorganism is placed to permit its growth, cause it to produce substances, or observe its activity under defined conditions; also called culture medium or growth medium. The medium is usually a solution of nutrients in water, or a similar solution solidified with gelatin or agar.
10. n. A means of transmission of news, advertising, or other messages from an information source to the public, also called a news medium, such as a newspaper or radio; used mostly in the plural form, i. e. news media or media. See 1st media{2}.
11. adj. Having a middle position or degree; mean; intermediate; medial.

WordNet 3.0

1. n. an occupation for which you are especially well suited
2. n. an intervening substance through which something is achieved
3. n. the surrounding environment
4. adj. around the middle of a scale of evaluation
5. n. a state that is intermediate between extremes; a middle position
6. n. a means or instrumentality for storing or communicating information
7. n. (bacteriology) a nutrient substance (solid or liquid) that is used to cultivate micro-organisms
8. n. someone who serves as an intermediary between the living and the dead
9. n. a liquid with which pigment is mixed by a painter
10. n. (biology) a substance in which specimens are preserved or displayed
11. n. an intervening substance through which signals can travel as a means for communication
12. n. (usually plural) transmissions that are disseminated widely to the public
13. adj. (meat) cooked until there is just a little pink meat inside