What is "ultra-"

Ultra- \Ul"tra-\, a. A prefix from the Latin ultra beyond (see Ulterior), having in composition the signification beyond, on the other side, chiefly when joined with words expressing relations of place; as, ultramarine, ultramontane, ultramundane, ultratropical, etc. In other relations it has the sense of excessively, exceedingly, beyond what is common, natural, right, or proper; as, ultraconservative; ultrademocratic, ultradespotic, ultraliberal, ultraradical, etc.

word-forming element meaning "beyond" (ultraviolet) or "extremely" (ultramodern), from Latin ultra- from ultra (adv. and prep.) "beyond, on the other side, on the farther side, past, over, across," from PIE *ol-tero-, suffixed form of root *al- (1) "beyond" (see alias (adv.)). In common use from early 19c., it appears to have arisen from French political designations. As its own word, a noun meaning "extremist" of various stripes, it is first recorded 1817, from French ultra, shortening of ultra-royaliste "extreme royalist."

pre. 1 greater than normal quantity or importance, as in ultrasecret. 2 beyond, on the far side of, as in ultraviolet. 3 beyond, outside of, as in ultrasonic. 4 excessively, to an extreme, as in ultramicroscopic, ultra-careful.