holonymy

Holonymy is a semantic relation in which a word denotes a whole and another word denotes a part of that whole. In a holonym–meronym pair, the holonym names the entire object or concept, while the meronym names one of its components. The relation captures part–whole structure in lexical semantics and cognitive linguistics.

Common examples include car as a holonym of wheel and engine, and wheel as a meronym of car. Similarly, tree is a holonym of branch and leaf; body is a holonym of hand, arm, and leg. A forest may be described as a holonym of trees, and a book as a holonym of pages. Note that a part can have multiple holonyms across contexts, and a single part may be found in multiple wholes (for example, a wheel can be part of many different vehicles).

Holonymy is distinct from hypernymy, which relates generalization rather than part–whole structure. In practice, lexical databases such as WordNet encode holonymy and meronymy as explicit relations, aiding tasks in natural language processing, information retrieval, and knowledge representation. The notion is language- and domain-specific; some languages or domains treat part–whole relationships differently, and boundaries between parts and wholes can be fuzzy.