A mustache is the strip of hair that grows on a person's upper lip, between the nose and mouth. Some people grow their mustaches long and thick, while others keep them neatly trimmed. Throughout history, mustaches have gone in and out of fashion: soldiers in World War I often wore them, and many famous figures from Mark Twain to Albert Einstein sported distinctive mustaches that became part of how people remembered them.

You might see it spelled moustache in British English, but both spellings mean the same thing.

Different cultures and time periods have treated mustaches differently. In some places and eras, a thick mustache was seen as dignified and mature. In others, being clean-shaven was the style. Some mustache styles even have special names, like the handlebar mustache that curls up at the ends, or the pencil mustache, which is trimmed to a thin line.

Today, people grow mustaches for all sorts of reasons: personal style, tradition, or simply because they like how it looks. Some people can't grow much facial hair at all, while others can grow a full mustache in just a few weeks.