Athletes or sports enthusiasts; also a term for athletic supporters or straps worn under clothing during sports.
Short for 'jockey,' originally referring to someone who rides horses, but by the early 20th century it was American slang for athletes in general, especially at schools and colleges.
Calling athletes 'jocks' started because they wore 'jock straps'—so the word went from being equipment to defining an entire social group at schools, which shows how slang can accidentally create stereotypes!
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