Bocardo

Bo·car·do

Bocardo

n.
  1. A form of syllogism of which the first and third propositions are particular negatives, and the middle term a universal affirmative. (Logic)
    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.]