Semilattice
Full definition of semilattice
Noun
semilattice
(plural semilattices)- (mathematics) A partially ordered set that either has a join (a least upper bound) for any nonempty finite subset (a join-semilattice or upper semilattice) or has a meet (or greatest lower bound) for any nonempty finite subset (a meet-semilattice or lower semilattice).