ˈmikəlməs noun
( -es )
Usage: usually capitalized
Etymology: Middle English mychelmesse, from Old English Michaeles mæsse, from Michaeles (gen. of Michael, archangel identified as patron of the Jewish nation in Daniel 10:21 and as leader in a war against the devil in Rev 12:7-9) + Old English mæsse mass, feast day — more at mass
: the feast of the archangel Michael that is a church festival celebrated on September 29 and is one of the four quarter days in England