The part–whole relationship is sometimes referred to as HAS-A, and corresponds to object composition in object-oriented programming.
[1] The study of meronomy is known as mereology, and in linguistics a meronym is the name given to a constituent part of, a substance of, or a member of something.
In formal terms, in the context of knowledge representation and ontologies, a meronomy is a partial order of concept types by the part–whole relation.
[3] In the classic study of parts and wholes, mereology, the three defining properties of a partial order serve as axioms.
[4] They are, respectively, that the part-of relation is Meronomies may be represented in semantic web languages such as OWL and SKOS.