round rob·in • n. 1. [often as adj.] a tournament in which each competitor plays in turn against every other: a round-robin competition.2. a petition, esp. one with signatures written in a circle to conceal the order of writing. ∎ a letter written by several people in turn, each person adding text before passing the letter on to someone else: [as adj.] a round-robin letter. 3. a series or sequence: an inconclusive round robin of talks in Cairo, Washington, and New York.