late 14c., originally in the mathematical sense, from Anglo-French fraccioun (Old French fraccion, "a breaking," 12c., Modern French fraction) and directly from Late Latin fractionem (nominative fractio) "a breaking," especially into pieces, in Medieval Latin "a fragment, portion," noun of action from past participle stem of Latin frangere "to break (something) in pieces, shatter, fracture," from Proto-Italic *frang-, from a nasalized variant of PIE root *bhreg- "to break" (cognates: Sanskrit (giri)-bhraj "breaking-forth (out of the mountains);" Gothic brikan, Old English brecan "to break;" Lithuanian brasketi "crash, crack;" Old Irish braigim "break wind"). Meaning "a breaking or dividing" in English is from early 15c.; sense of "broken off piece, fragment," is from c.1600.