bocardo

from The Century Dictionary.

• noun In logic, the mnemonic name of that mood of the third figure of syllogism in which the major premise is a particular negative, the minor a universal affirmative, and the conclusion a particular negative proposition: as, Some patriarchs (Enoch, Elijah) are not mortal; but all patriarchs are men; hence, some men are not mortal.
• noun A prison: so called from the old north gate of Oxford, which had this name and was at one time used as a prison.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Logic) A form of syllogism of which the first and third propositions are particular negatives, and the middle term a universal affirmative.
• noun engraving A prison; -- originally the name of the old north gate in Oxford, which was used as a prison.