Bocardo \Bo*car"do\, n. [A mnemonic word.] 1. (Logic) A form of syllogism of which the first and third propositions are particular negatives, and the middle term a universal affirmative. Baroko and Bocardo have been stumbling blocks to the logicians. --Bowen. 2. A prison; -- originally the name of the old north gate in Oxford, which was used as a prison. [Eng.] --Latimer.