The word 'tux' is a direct American English shortening of 'tuxedo', which entered common usage in the early 20th century. 'Tuxedo' itself originates from Tuxedo Park, an exclusive country club and residential enclave in New York, where the tailless dinner jacket was popularized in the 1880s. The place name 'Tuxedo' is derived from a Lenape (Algonquian) word, p'tuksit, meaning "round foot" or "wolf", likely referring to a local animal or geographical feature. Thus, the modern term for formalwear is a fascinating linguistic journey from an indigenous American word, to a prestigious location, to a style of clothing, and finally to its clipped, casual form.

The word 'tux' is a clipped form (hypocorism) of 'tuxedo'. It does not contain separable morphemes in its current spelling.