feed v.

*pā-, Proto-Indo-European root meaning "to protect, feed."

It forms all or part of: antipasto; appanage; bannock; bezoar; companion; company; feed; fodder; food; forage; foray; foster; fur; furrier; impanate; pabulum; panatela; panic (n.2) "type of grass;" pannier; panocha; pantry; pastern; pastor; pasture; pester; repast; satrap.

It is the hypothetical source of/evidence for its existence is provided by: Greek pateisthai "to feed;" Latin pabulum "food, fodder," panis "bread," pasci "to feed," pascare "to graze, pasture, feed," pastor "shepherd," literally "feeder;" Avestan pitu- "food;" Old Church Slavonic pasti "feed cattle, pasture;" Russian pishcha "food;" Old English foda, Gothic fodeins "food, nourishment."

past-participle adjective from feed (v.). Fed up "surfeited, disgusted, bored," is British slang first recorded 1900 (some early uses connect it to the Boer War), extended to U.S. by World War I; probably from earlier phrases like fed up to the back teeth. Earlier it was used of livestock, "fatten up by feeding." The notion probably is the same one in to have had enough "to have had too much."