cohyponymy

Cohyponymy denotes a semantic relation between two terms that are both hyponyms of the same broader term. In a hierarchical lexicon, such words are siblings under a shared hypernym, hence cohyponyms. The relation is defined at the level of specific senses, so whether two terms are cohyponyms can depend on which senses are intended; a word with multiple senses may be cohyponymous with another sense in some contexts but not in others.

Examples include dog and cat as cohyponyms of animal; rose and tulip as cohyponyms of flower; car and truck as cohyponyms of vehicle. Cohyponyms are related through their common hypernym but need not be closely related in meaning beyond this shared category; they occupy the same semantic field and are often listed or discussed together in lexical domains.

In linguistics and natural language processing, cohyponymy appears in lexical resources such as WordNet as sibling synsets sharing a hypernym. It informs semantic similarity, clustering, and word sense disambiguation, although practical use must account for polysemy, domain specificity, and cross-language variation.