Definition:Figure of Categorical Syllogism

Definition
There are four patterns of categorical syllogism depending on the order of the terms in the major premise and minor premise.

Let $\mathbf \Phi_1, \mathbf \Phi_2, \mathbf \Phi_3$ each be one of $\mathbf A$, $\mathbf E$, $\mathbf I$ or $\mathbf O$.

Let $P$ denote the primary term, $S$ denote the secondary term and $M$ denote the middle term.

The four possible figures are as follows: