Why is the ninth month called September?
"angry dispute," mid-14c., originally "ground for complaint," from Old French querele "matter, concern, business; dispute, controversy" (Modern French querelle), from Latin querella "complaint, accusation; lamentation," from queri "to complain, lament." Replaced Old English sacan. Sense of "contention between persons" is from 1570s.
"square-headed bolt for a crossbow," mid-13c., from Old French quarel, carrel "bolt, arrow," from Vulgar Latin *quadrellus, diminutive of Late Latin quadrus (adj.) "square," related to quattuor "four" (see four). Now-archaic sense of "square or diamond-shaped plane of glass" first recorded mid-15c.
late 14c., "to raise an objection;" 1520s as "to contend violently, to fall out," from quarrel (n.1) and in part from Old French quereler (Modern French quereller). Related: Quarrelled; quarrelling.