Why is the ninth month called September?
mid-14c., abbreviation of buglehorn "musical horn, hunting horn" (c.1300), from Old French bugle "(musical) horn," also "wild ox, buffalo," from Latin buculus "heifer, young ox," diminutive of bos "ox, cow" (see cow (n.)). Middle English also had the word in the "buffalo" sense and it survived in dialect with meaning "young bull." Modern French bugle is a 19c. borrowing from English.