Definition
A 'head word' is the word that begins an entry in a dictionary or other reference work; also called an entry word or main entry. Think of it like the title of a chapter in a book. It is the word being defined, explained, or described. The head word acts as the primary focus for the information that follows. It is like the subject of a sentence. In a dictionary, it's the word in bold. If you are looking up 'serendipity,' that's the head word.