—n. 1. a middle state or condition; mean.
2. something intermediate in nature or degree.
3. an intervening substance, as air, through which a force acts or an effect is produced.
4. the element that is the natural habitat of an organism.
5. surrounding objects, conditions, or influences; environment.
6. an intervening agency, means, or instrument by which something is conveyed or accomplished: Words are a medium of expression. 7. one of the means or channels of general communication, information, or entertainment in society, as newspapers, radio, or television.
8. Biol.the substance in which specimens are displayed or preserved.
9. Also calledculture medium.Bacteriol.a liquid or solidified nutrient material suitable for the cultivation of microorganisms.
10. a person through whom the spirits of the dead are alleged to be able to contact the living.
11. Fine Arts. a. Painting.a liquid with which pigments are mixed.
b. the material or technique with which an artist works: the medium of watercolor. 12. a size of printing paper, 18½ × 23½ in. (47 × 60 cm) in England, 18 × 23 to 19 × 25 in. (46 × 58 to 48 × 64 cm) in America.
13. Chiefly Brit.a size of drawing or writing paper, 17½ × 22 in. (44 × 56 cm).
14. Also called medium strip.Midland U.S.See median strip. 15. in medium,Motion Pictures,Television.with the principal actors in the middle distance: The scene was shot in medium.
—adj. about halfway between extremes, as of degree, amount, quality, position, or size: Cook over medium heat. He is of medium height.