A lightsaber is the signature weapon of the Jedi and Sith in the Star Wars movies and books. It looks like a glowing sword made of pure energy, usually about three feet long, that extends from a metal handle called a hilt. Different lightsabers glow in different colors: Jedi typically carry blue or green ones, while Sith wield red blades.

In the Star Wars universe, lightsabers can cut through almost anything (except another lightsaber blade), making them incredibly powerful weapons. But they're also extremely difficult to use safely. Only Force-users, people with special powers, have the reflexes and training needed to wield them effectively. Building your own lightsaber is considered an important milestone in a Jedi's training.

Outside of Star Wars, people use lightsaber to describe anything that resembles the glowing energy blade, or to talk about Star Wars fandom in general. Kids might have lightsaber duels with toy versions that light up and make humming sounds. The weapon has become one of the most recognizable symbols in science fiction, representing the struggle between good and evil, discipline and chaos.