anastrophe n.

before vowels an-, word-forming element meaning: 1. "upward, up in place or time," 2. "back, backward, against," 3. "again, anew," from Greek ana (prep.) "up, on, upon; up to, toward; throughout; back, backwards; again, anew," from an extended form of PIE root *an- (1) "on, upon, above" (see on, which is the English cognate). In old medical prescriptions, ana by itself meant "an equal quantity of each."

Proto-Indo-European root meaning "to wind, turn."

It forms all or part of: anastrophe; antistrophe; apostrophe (n.1); apostrophe (n.2); boustrophedon; catastrophe; epistrophe; strabismus; strap; strep; strepto-; streptococcus; streptomycin; strobe; strobic; stroboscope; strop; strophe; strophic.

It is the hypothetical source of/evidence for its existence is provided by: Greek strophe "stanza," originally "a turning," strephein "to turn," strophaligs "whirl, whirlwind," streblos "twisted," stremma "that which is twisted."