1. Plural of porism; a mathematical proposition or corollary that follows naturally from a preceding theorem or proof.
Usage: mathematics; formal; technical
2. In classical geometry, a type of theorem stating that under certain conditions a construction is possible, or that a certain property holds for an infinite class of figures.
Usage: mathematics; archaic; historical

Examples

• The porisms in Euclid's Elements demonstrate how certain geometric truths follow from established theorems.
• Ancient mathematicians used porisms to extend the reach of their proofs beyond single cases.
• The study of porisms reveals the elegant logical structure underlying classical geometry.
• Several porisms in the text provide shortcuts for solving complex geometric problems.