Why is the ninth month called September?
mid-15c., arang, Scottish (in English from c.1600), from Middle French harangue (14c.), from Italian aringo "public square, platform," from a Germanic source ultimately from or including Proto-Germanic *ring "circular gathering" (see ring (n.1)). Perhaps it is ultimately from Gothic *hriggs (pronounced "hrings"), with the first -a- inserted to ease Romanic pronunciation of Germanic hr- (cf. hamper (n.)). But Barnhart suggests a Germanic compound, hari-hring "circular gathering," literally "army-ring."
1650s, from French haranguer, from Middle French harangue (see harangue (n.)). Related: Harangued; haranguing.