Lattice

1. A partially ordered mathematical set for which every pair of elements has a greater lower bound and a least upper bound [CESG]. Note: A lattice may be used to represent the relationship between security classes. A security clearance specifies the least upper bound of security classes of objects for which access rights may be granted. See also: Dominance. 2. A partially ordered set for which every pair of elements has a greatest lower bound and a least upper bound [TCSEC].