gall (n.1) Look up gall at Dictionary.com
"bile," Old English galla (Anglian), gealla (West Saxon) "gall, bile," from Proto-Germanic *gallon- "bile" (cognates: Old Norse gall, Old Saxon, Old High German galla, German Galle), from PIE root *ghel- (2) "to shine," with derivatives referring to bright materials and gold, and bile or gall (see glass). Informal sense of "impudence, boldness" first recorded American English 1882; but meaning "embittered spirit, rancor" is from c.1200, from the medieval theory of humors. Gall bladder recorded from 1670s.
gall (n.2) Look up gall at Dictionary.com
"sore spot on a horse," Old English gealla "painful swelling," from Latin galla "gall, lump on plant," originally "oak apple," of uncertain origin. Perhaps from or influenced by gall (1) on notion of "poison-sore." German galle, Dutch gal also are from Latin.
gall (v.) Look up gall at Dictionary.com
"to make sore by chafing," mid-15c., from gall (n.2). Earlier "to have sores, be sore" (early 14c.). Figurative sense of "harass, irritate" is from 1570s. Related: Galled; galling.