##### The Collaborative International Dictionary

**Porism**

Porism \Po"rism\, n. [Gr. ? a thing procured, a deduction from a demonstration, fr. ? to bring, provide: cf. F. porisme.]

(Geom.) A proposition affirming the possibility of finding such conditions as will render a certain determinate problem indeterminate or capable of innumerable solutions.

--Playfair.-
(Gr. Geom.) A corollary.

--Brande & C.Note: Three books of porisms of Euclid have been lost, but several attempts to determine the nature of these propositions and to restore them have been made by modern geometers.

##### Wiktionary

**porism**

n. 1 (context geometry English) A proposition affirming the possibility of finding such conditions as will render a certain determinate problem indeterminate or capable of innumerable solutions. 2 A corollary.

##### Wikipedia

**Porism**

A **porism** is a mathematical proposition or corollary. In particular, the term **porism** has been used to refer to a direct result of a proof, analogous to how a corollary refers to a direct result of a theorem. In modern usage, a **porism** is a relation that holds for an infinite range of values but only if a certain condition is assumed, for example Steiner's porism. The term originates from three books of Euclid with porism, that have been lost. Note that a proposition may not have been proven, so a porism may not be a theorem, or for that matter, it may not be true.

#### Usage examples of "porism".

It is not quite clear what a __porism__ was to Euclid but from later commentators it appears to have been a conception intermediate between a theorem and a problem.