Definition:Join


 * Group theory:
 * Join of Subgroups: the subgroup formed by the union of two subgroups.


 * Order Theory
 * Join (Order Theory): the supremum of the set formed by two elements of an ordered set.


 * Graph Theory
 * Join (Graph Theory): an edge joins two vertices of a graph.


 * Set Theory
 * A term (rarely used nowadays) for set union.