A transitive parthood relation in which one entity has itself, or another entity as part, and the relation is valid for use between continuants or between occurrents but not between a continuant and an occurrent . We also note that has_part is not an inverse-relation of part_of. The has_part relation between continuants is time-dependent while it is time-independent between occurrents.

If C and C1 are continuant classes, then C has_part C1 means that every instance of C, at any time, has some instances of C1 as parts at the same time.

Primary Amine has_part Primary Amine Group

Thiol has_part Sulfhydryl Group

If P and P1 are occurrent classes, then P has_part P1 means that every instance of P has some (one or more) instances of P1 as parts.

Nanoparticle Characterization has_part In Vitro Characterization

Smith B, Ceusters W, Klagges B, Kohler J, Kumar A, Lomax J, Mungall C, Neuhaus F, Rector AL, Rosse C: Relations in biomedical ontologies. Genome Biol 2005, 6: R46.