"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.
