To enlist means to join the military by signing up to serve. When someone enlists in the Army, Navy, Air Force, Marines, or Coast Guard, they volunteer to become a soldier, sailor, airman, or marine. The person who enlists is called an enlisted member or an enlistee.

Enlisted members form the backbone of the military, carrying out the essential work of defending the country. They start at entry-level ranks like Private or Seaman and can advance through hard work and dedication. This is different from officers, who usually begin their military careers after graduating from college or special training academies and who serve in leadership positions.

You can also enlist someone's help with something challenging: “I enlisted my older sister's help with my science project” means you asked her to join your effort and she agreed. When you enlist support for a cause, you're recruiting people to your side, similar to how the military recruits new members. In both cases, enlisting means getting someone to commit to helping with something important.