Etymology

From German Januar, by pronunciation, and reinforced by cognates, from Latin iānuārius ‎(“(month) of Janus”), from the name of the god Iānus ‎(“Janus”), from iānus ‎(“arcade, covered passageway”), possibly from Proto-Indo-European *ei- ‎(“to go”), same source as Old Church Slavonic йадо ‎(йado, “to travel”) and Sanskrit यान ‎(yāna, “path”).