a person trained to compete in sports; an athlete.

athletic supporter

The term Jock is a classic American stereotype of an athlete. Sports which emphasize body mass are commonly labeled 'jock sports', e.g., American football, wrestling, weightlifting, and boxing. Because young people compose most participants in these sports, the jock stereotype is mostly centered on high schools, colleges, and spectator sports entertainment, as well as erotica associated with these.

"Jock" is the pseudonym of British comics artist Mark Simpson, most known for his work with Andy Diggle in 2000 AD and on The Losers.

A Scotch soldier.

colloq.] (Scottish variant of 'Jack') Scotsman

All things jock strap. Hunks in jocks etc.

a support for the genitals worn by men engaging in strenuous exercise

A disk jockey.

A jockstrap.