To reelect someone means to vote them into the same position they already hold, giving them another term in office. When voters reelect a mayor, governor, or president, they're saying “you did a good job, so we want you to keep doing it.”

The prefix “re” means “again,” so reelecting is literally electing again. Most elected officials serve for a set period called a term. A president's term lasts four years, and a senator's lasts six. When that term ends, the official can run for reelection, asking voters to choose them once more.

Voters reelect officials they think have done well, or at least better than the alternatives. Sometimes an official wins reelection easily because most people are satisfied. Other times the race is close because voters are divided about their performance. In the United States, some positions have term limits that prevent someone from being reelected indefinitely. For example, a president can only be elected twice, so after serving two terms, they cannot run for reelection no matter how popular they are.

The same idea applies beyond politics too. A club might reelect its president, or a student council might reelect its treasurer, though people more commonly just say “elect” in these cases even when it's the second or third time.