From definiens - Wiktionary:
(semantics) The word or phrase that defines the definiendum in a definition.
In the defining statement “A lake is a large, landlocked, naturally occurring stretch of water”, “large, landlocked, naturally occurring stretch of water” is the definiens.
But what is the term to describe “large", "landlocked", "naturally", etc? Definiens also? All I know that if we have a definition "An elephant is an animal", then animal is a hypernym of elephant.
Also: Definition - Wikipedia