post-modern (adj.) Look up post-modern at
also post-modern, post modern, by 1919, in frequent use from 1949, from post- + modern.
But it has been only during the later decades of the modern era -- during that time interval that might fairly be called the post-modern era -- that this mechanistic conception of things has begun seriously to affect the current system of knowledge and belief; and it has not hitherto seriously taken effect except in technology and in the material sciences. [Thorstein Veblen, "The Vested Interests and the Common Man," 1919]

So much for the misapplied theory which has helped set the artist's nerves a-quiver and incited him to the extremes of post modern art, literary and other. [Wilson Follett, "Literature and Bad Nerves," "Harper's," June 1921]
Of architecture from 1940s; specific sense in the arts emerged 1960s (see postmodernism).