Complex sentence: In mathematics, a lattice is a partially ordered set in which every two elements have a supremum (also called a least upper bound or join) and an infimum (also called a greatest lower bound or meet).
Split into simpler sentences: In mathematics, a lattice is a partially ordered set. In every two element subset of a lattice, one is a supremum (also called a least upper bound or join) and the other is an infimum (also called a greatest lower bound or meet).