lead·er 
/ˈli:dɚ/ noun
plural lead·ers /ˈli:dɚ/ noun [count] 1 : someone or something that leads others: such as a : someone who guides other people
▪ He acted as our leader [=guide] on the climb. ▪ The tour leader suggested several restaurants in the area.
b : someone or something that is ahead of others in a race or competition
▪ She was the leader for most of the race, but she eventually finished second. ▪ He is the league leader in home runs. [=he has the most home runs in the league] ▪ the leader board [=the list of players who are leading a golf tournament]
c : a powerful person who controls or influences what other people do : a person who leads a group, organization, country, etc.
▪ The class focused on the great religious/political leaders of the last century. ▪ the leader of an army ▪ a gang leader ▪ a leader of the antiwar movement ▪ Some people are leaders, and some people are followers. ▪ He's a born/natural leader. [=someone who has qualities that a good leader has]
d : a person, group, or organization that is the best or most successful in some activity
▪ The company has become a leader in developing new technology. ▪ a market leader [=a product or company that is more successful than all competing products or companies] 2 a : a person who leads a musical group
▪ the leader of a popular big band of the 1930s ; specifically US : the conductor of an orchestra
▪ the orchestra leader
b Brit : concertmaster 3 Brit : 2editorial
▪ The Times attacked the government in a leader today.
▪ He acted as our leader [=guide] on the climb. ▪ The tour leader suggested several restaurants in the area.
b : someone or something that is ahead of others in a race or competition
▪ She was the leader for most of the race, but she eventually finished second. ▪ He is the league leader in home runs. [=he has the most home runs in the league] ▪ the leader board [=the list of players who are leading a golf tournament]
c : a powerful person who controls or influences what other people do : a person who leads a group, organization, country, etc.
▪ The class focused on the great religious/political leaders of the last century. ▪ the leader of an army ▪ a gang leader ▪ a leader of the antiwar movement ▪ Some people are leaders, and some people are followers. ▪ He's a born/natural leader. [=someone who has qualities that a good leader has]
d : a person, group, or organization that is the best or most successful in some activity
▪ The company has become a leader in developing new technology. ▪ a market leader [=a product or company that is more successful than all competing products or companies]
▪ the leader of a popular big band of the 1930s ; specifically US : the conductor of an orchestra
▪ the orchestra leader
b Brit : concertmaster
▪ The Times attacked the government in a leader today.
— see also loss leader
— lead·er·less adjective
▪ a leaderless political movement
▪ a leaderless political movement
