Other forms: definientia
Here is a definiens for definiens: the part of a dictionary or glossary entry that provides the meaning of a word.
A dictionary entry usually has multiple parts, such as a pronunciation, part of speech, example sentences, and perhaps some engaging blurbs, etc. The word that is being defined is the definiendum, and the text that follows it to explain the word's meaning is the definiens. You can have more than one definiens per dictionary entry, as words often have many different meanings or shades of meaning.