ancient Italic deity, guardian god of portals, doors, and gates; patron of beginnings and endings, c.1500, from Latin Ianus, literally "gate, arched passageway," perhaps from PIE root *ei- "to go" (cf. Sanskrit yanah "path," Old Church Slavonic jado "to travel"). He is shown as having two faces, one in front the other in back. His temple in Rome was closed only in times of peace.
The Roman god of doors and gateways and hence of beginnings.
Note: Janus was pictured with two faces looking in opposite directions, one young and one old. Consequently, a hypocritical person is often called “Janus-faced.”
Note: The month of January is named after Janus.