- medium (n.)
- 1584, "a middle ground, quality, or degree," from L. medium, from neut. of adj. medius (see medial). Meaning "intermediate agency, channel of communication" is from 1605. That of "person who conveys spiritual messages" first recorded 1853, from notion of "substance through which something is conveyed." Artistic sense (oil, watercolors, etc.) is from 1854. The adj. is 1670, from the noun; as a designation of cooked meat, it is attested from 1939. Happy medium is the "golden mean," Horace's aurea mediocritas.