"of or pertaining to present or recent times," 1500, from M.Fr. moderne, from L.L. modernus "modern," from L. modo "just now, in a (certain) manner," from modo "to the measure," abl. of modus "manner, measure"). In Shakespeare, often with a sense of "every-day, ordinary, commonplace." Slang abbreviation mod first attested 1960. Modern art is from 1849; modern dance first attested 1912; first record of modern jazz is from 1955. Modern conveniences first recorded 1926. Modernize is from 1748 (implied in modernized).
as a movement in the arts, 1929, from modern (q.v.). The word dates to 1737 in the sense of "deviation from the ancient and classical manner" [Johnson, who calls it "a word invented by Swift"]. It has been used in theology since 1901.
1949, from post- + modern. Originally in architecture writing; specific sense in the arts emerged 1960s. Postmodernism defined by Terry Eagleton as "the contemporary movement of thought which rejects ... the possibility of objective knowledge" and is therefore "skeptical of truth, unity, and progress."