hyponym

n. (linguistics) a word that is more specific (less abstract) than a given word; a term designating a class which is a subtype of the given word; a subcategory; a subtype. Inverse of hypernym; as, “dog” is a hyponym of “mammal”, and “mammal” is a hyponym of “vertebrate”.
Syn. -- subordinate, subordinate word. [ WordNet 1.5 ]