The verb sack has many different meanings: it can refer to someone being fired, to a play in football, to the plundering of a city, or the action of putting something in a bag. The first two come from the "pillage" definition, which in turn comes from the French phrase mettre a sac, meaning "put it in a bag" (on the notion of packing up booty). That's essentially equivalent to the last definition, which just comes from the noun. Eventually, it all traces to Proto-Germanic sakkuz, a borrowing from Latin saccus, which meant "large bag" (and is the etymon of terms like sac, satchel, and saccade). Finally, that, through Ancient Greek sakkos, is thought to ultimately derive from Proto-Semitic due to cognates in Hebrew saq and other Middle Eastern languages. Usage of the word sack in literature over time has been fairly constant since the eighteenth century.
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.