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.