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"unstressed syllable at the beginning of a verse," 1833, Latinized from Greek anakrousis "a pushing back," of a ship, "backing water," from anakrouein "to push back, stop short, check," from ana- "back" (see ana-) + krouein "to strike," from PIE *kreue- (2) "to push, strike" (cf. Russian krusit, Lithuanian krusu "to smash, shatter," Old Church Slavonic kruchu "piece, bit of food," Old English hreowian "feel pain or sorrow," Old Norse hryggja "make sad").
in classical prosody, the up (or weak) beat, one or more syllables at the beginning of a line of poetry that are not regarded as a part of the metrical pattern of that line. Some scholars do not acknowledge this phenomenon. The term is from the Greek anakrousis, meaning "the act of pushing back," or "beginning of a tune."