A tux is a formal suit that people wear to very special events like weddings, award ceremonies, or fancy dances. The word is short for tuxedo. A tux is usually black or dark blue, with a jacket that has silk or satin lapels (the folded-back parts near the collar) that give it a distinctive shine. The jacket is worn with matching dress pants that have a stripe down each leg, plus a white shirt, a black bow tie, and often a cummerbund (a wide fabric band worn around the waist).

Before tuxes became popular, men wore tailcoats to formal events, which had long tails hanging down the back. The tux was considered more modern and comfortable.

When someone needs to dress up for the fanciest occasion they can imagine, like a black-tie wedding or a high school prom, they might rent or buy a tux. Wearing one signals that the event is genuinely important and that you're showing respect by dressing your absolute best.