- pro (n.1)
- 1866, shortening of professional (n.). The adjective is first recorded 1915 (in golfing's pro shop).
- pro (n.2)
- "a consideration or argument in favor," c. 1400, from Latin pro (see pro-). Pro and con is attested from c. 1400, short for pro and contra "for and against" (Latin pro et contra).