Taken from the month name, which comes from Janus, the Roman god of beginnings and doorways.
January takes its name from Janus, the Roman god of beginnings, transitions, doorways, and time itself — the only major deity in the Roman pantheon with no Greek equivalent, distinctly Latin in origin. Janus was depicted with two faces looking simultaneously forward and backward, perfectly embodying the liminal quality of the year's first month, when one looks back at what has passed and forward into the unknown. The month name Ianuarius was in use by at least the 8th century BC, making January one of the oldest Latin words that survives in common daily use.
As a given name, January is bracingly unconventional. Month names have occasionally crossed into personal names — April, May, and June have long histories as feminine given names — but January has a crisper, more architectural quality. It gained cultural visibility through figures like January Jones, the American actress, whose name drew renewed attention to its possibilities.
The name suits any gender and wears its calendar origins lightly: most people immediately understand it yet rarely meet another bearer. Giving a child the name of the threshold month carries a beautiful implicit meaning: a person who stands at beginnings, who bridges old and new, who faces both directions with clear eyes. In a culture increasingly drawn to names that feel both distinctive and pronounceable, January strikes an unusual balance — it requires no explanation, conjures immediate imagery, and yet remains genuinely rare on playgrounds and in classrooms. It is a name that arrives with its own mythology already intact.