- See also changes related to Union, or pages that link to Union or to this page or whose text contains "Union".
- Set (mathematics) [r]: Informally, any collection of distinct elements. [e]
- Set theory [r]: Mathematical theory that models collections of (mathematical) objects and studies their properties. [e]
- Disjoint union [r]: A set containing a copy of each of a family of two or more sets, so that the copies do not overlap. [e]
- Intersection [r]: The set of elements that are contained in all of a given family of two or more sets. [e]