leader

UK: /ˈliːdə^r/ US: /ˈlidɚ/ ,(lē′dər)

WordReference Random House Learner's Dictionary of American English © 2025

lead•er /ˈlidɚ/   n. [countable]

1. one that leads.

WordReference Random House Unabridged Dictionary of American English © 2025

lead•er  (lē′dər), n. 

1. a person or thing that leads.
2. a guiding or directing head, as of an army, movement, or political group.
3. Music and Dance
   • a conductor or director, as of an orchestra, band, or chorus.
   • the player at the head of the first violins in an orchestra, the principal cornetist in a band, or the principal soprano in a chorus, to whom any incidental solos are usually assigned.
4. a featured article of trade, esp. one offered at a low price to attract customers. Cf. loss leader.
5. [Journalism.]
   • Journalism See leading article (def. 1).
   • British Terms Also called leading article. the principal editorial in a newspaper.
6. Cinema blank film or tape at the beginning of a length of film or magnetic tape, used for threading a motion-picture camera, tape recorder, etc. Cf. trailer (def. 6).
7. Sport [Angling.]
   • a length of nylon, silkworm gut, wire, or the like, to which the lure or hook is attached.
   • the net used to direct fish into a weir, pound, etc.
8. Building a pipe for conveying rain water downward, as from a roof;
   downspout.
9. a horse harnessed at the front of a team.
10. Printing leaders, a row of dots or a short line to lead the eye across a space.
11. Nautical, Naval Terms lead¹ (def. 46b).
12. Building a duct for conveying warm air from a hot-air furnace to a register or stack.
13. Mining a thin vein of ore connected with a large vein.

• Middle English leder(e). See lead¹, -er¹ 1250–1300

lead′er•less, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

leader / ˈliːdə/ noun

1. a person who rules, guides, or inspires others; head
2. 
   Also called (esp US and Canadian): concertmaster the principal first violinist of an orchestra, who plays solo parts, and acts as the conductor's deputy and spokesperson for the orchestra
3. a conductor or director of an orchestra or chorus
4. the first person on a climbing rope
5. the leading horse or dog in a team
6. an article offered at a sufficiently low price to attract customers
   See also loss leader
7. Also called: leading article the leading editorial in a newspaper
8. another word for trace22
9. a strip of blank film or tape used to facilitate threading a projector, developing machine, etc, and to aid identification
10. (plural) rows of dots or hyphens used to guide the reader's eye across a page, as in a table of contents
11. any of the long slender shoots that grow from the stem or branch of a tree: usually removed during pruning
12. a member of the Government having primary authority in initiating legislative business (esp in the phrases Leader of the House of Commons and Leader of the House of Lords)
13. the senior barrister, usually a King's (or Queen's) Counsel, in charge of the conduct of a case
    Compare junior6

ˈleaderless adjective