Why is the ninth month called September?
c.1300, suowne, "state of unconsciousness," probably from Old English geswogen "in a faint," past participle of a lost verb *swogan, as in Old English aswogan "to choke," of uncertain origin. Cf. Low German swogen "to sigh."
c.1200, "to become unconscious," probably from a lost Old English verb *swogan (see swoon (n.)). Related: Swooned; swooning.