set theory

noun

1. the branch of mathematics that deals with relations between sets.

set theory

noun

1. maths the branch of mathematics concerned with the properties and interrelationships of sets
2. logic a theory constructed within first-order logic that yields the mathematical theory of classes, esp one that distinguishes sets from proper classes as a means of avoiding certain paradoxes

Word History and Origins

Origin of set theory¹

First recorded in 1940–45