1. Opposite Prompt. British term for Stage Right. See Opposite Prompt, OP and Prompt Side, PS. Since PS is (usually) Stage Left, OP is Stage Right. 2. Short for Operator, as in Board Op, Spot Op, Sound Op, etc. 3. Orchestra Pit, see Orchestra Pit. 4. In CB and other online forum parlance, may also stand for Original Poster--one who made a statement, as in "The OP said...", or Original Post.