A musketeer was a soldier who fought with a musket, an early type of gun that was common from the 1500s through the 1700s. Musketeers would load gunpowder and a metal ball into their long-barreled weapons, aim, and fire. Reloading took so long that musketeers often had to work in groups, with some firing while others reloaded.

The most famous musketeers were the Musketeers of the Guard, elite French soldiers who protected the king in the 1600s. They became legendary through Alexandre Dumas's adventure novel The Three Musketeers, which tells the story of d'Artagnan and his three friends Athos, Porthos, and Aramis. These fictional characters were inspired by real musketeers, and their motto “All for one, and one for all” captured the spirit of loyalty and friendship that made them heroes.

Today, when someone calls you a musketeer, they might be suggesting you're part of a tight-knit group of friends who stick together through thick and thin. The word reminds us that some of history's most celebrated warriors succeeded through their unwavering loyalty to each other as much as through their individual skill.