1. a person who leads or commands a group, organization, or country
2. a person who is ahead of others in a competition or activity
3. the main or most important item in a group

Examples

• She was elected as the leader of the student council.
• The team captain is a natural leader on the field.
• The runner from Kenya was the leader for most of the race.
• Our company is a leader in renewable energy technology.
• The political leader addressed the nation on television.
• He emerged as the leader in the polls after the debate.
• The tour leader guided us through the ancient ruins.