flay v.

Old English fleax "flax plant; cloth made with flax, linen," from Proto-Germanic *flakhsan (source also of Old Frisian flax, Middle Dutch and Dutch vlas, Old Saxon flas, Old High German flahs, German Flachs), probably from Proto-Germanic base *fleh- "to plait," from PIE root *plek- "to plait." But some connect it with PIE *pleik- (see flay) from the notion of "stripping" fiber to prepare it.

late 14c., "to spot, stain, cover with spots," probably from Old Norse flekka "to spot," from Proto-Germanic *flekk- (source also of Middle Dutch vlecke, Old High German flec, German Fleck), from PIE *pleik- "to tear" (see flay). Related: Flecked; flecking.

"side of bacon," Middle English flicche (c. 1200), "side of a slaughtered animal," especially the salted and cured side of a hog, from Old English flicce "flitch of bacon, ham," from Proto-Germanic *flekkja (source also of Old Norse flikki, Middle Low German vlicke "piece of flesh"). Not immediately from flesh (n.), but perhaps from the same PIE root, *pleik- "to tear" (see flay). The Flitch of Dunmow was presented every year at Little Dunmow, in Essex, to any married couple who could prove they had lived together without quarreling for a year and a day, a custom mentioned in early references as dating to mid-13c., revived 19c.