areola

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Biology A small space or interstice in a tissue or part, such as the area bounded by small veins in a leaf or the wing of an insect.
2. n. A small, specialized, cushionlike area on a cactus from which hairs, glochids, spines, branches, or flowers may arise.
3. n. Anatomy A small ring of color around a center portion, as about the nipple of the breast or the part of the iris surrounding the pupil of the eye.

Century Dictionary and Cyclopedia

1. n. In entomology, a small, generally angular, inclosed space on a surface, as the spaces between the veinlets in the wing of a dragon-fly, or pale spaces between dark lines which form a network. Also areolet.
2. n. In botany, a term sometimes used to designate the meshes of cellular tissue or little distinct angular spaces on a surface.
3. n. In anatomy: Any little cell, area, or space; especially, one of the small interstices in the meshes of areolar tissue and the like, or among minute interlacing vessels, as capillaries. The colored circle or halo about the nipple of the human mammary gland, pink in virgins, and brown of various shades in women who have borne children. The red ring of inflamed tissue surrounding a pustule. Hence, figuratively
4. n. An aureole.
5. n. In decorative art and manufacture, any plate, tile, or flat panel. A tile of earthenware, or a plate of marble or stone forming part of a pavement. One of the eight plates, rectangular, with arched tops, and richly jeweled and enameled, which make up the circuit of the imperial crown of the Byzantine empire and that of Charlemagne. See crown.
6. n. Also areole.
7. n. A tessellation in the thallus of some lichens.

Wiktionary

1. n. anatomy The colored circle around a nipple, more exactly known as areola mammae.
2. n. anatomy Any small circular area that is different from its immediate environment such as the colored ring around the pupil of the eye (iris) or an inflamed region surrounding a pimple.

GNU Webster's 1913

1. n. An interstice or small space, as between the cracks of the surface in certain crustaceous lichens; or as between the fibers composing organs or vessels that interlace; or as between the nervures of an insect's wing.
2. n. (Anat. & Med.) The colored ring around the nipple, or around a vesicle or pustule.

WordNet 3.0

1. n. small circular area such as that around the human nipple or an inflamed area around a pimple or insect bite
2. n. small space in a tissue or body part such as the area between veins on a leaf or an insect's wing