Taken from the month name December, from Latin decem meaning ten.
December arrives as a given name carrying the full weight of its Latin ancestry: from decem, meaning "ten," it was the tenth month in the early Roman calendar of Romulus, which began in March. When January and February were added, December was nudged to twelfth position, but the name was never updated — a charming linguistic fossil embedded in every winter calendar. As a word, it contains multitudes: the Roman festival of Saturnalia, the solstice darkness, the turn of the year, the particular quality of light in late afternoons when snow is possible.
As a given name, December is a genuinely modern invention, part of the broader nature-name and word-name movement that gained momentum in the late twentieth and early twenty-first centuries. Names like January, April, and August had long existed as given names, but December remained almost exclusively in the realm of calendars until parents began embracing it for children born in the twelfth month or simply for its cool, crystalline sound. It sits in the company of names like Winter, Frost, and Solstice — names that place a child in the turning of the natural year.
December carries a romanticism that comes partly from the holiday associations particular to each family's tradition, and partly from the name's sheer rarity. It is almost unheard of in historical records as a personal name, making every person named December a small pioneer. The name works differently depending on whether a child is, in fact, a December baby — for those who are, the month of birth becomes permanently woven into identity.