A definition states the essential necessary and sufficient attributes of a thing

Evidence

“A ‘definition,’ ” according to Aristotle, “is a phrase signifying a thing’s essence.” By the essence of a thing he understood the set of fundamental attributes which are the necessary and sufficient conditions for any concrete thing to be a thing of that type. It approximates to what we have called the conventional intension of a term. — Gary Goertz, Social Science Concepts, 479

Categorization

• DEFINE: Pins down ‘intension’ via Aristotle’s essence: the necessary and sufficient attributes that make something a member of a type.
• XREF: Connects to the book’s earlier treatment of conventional intension and to Sartori’s classic ‘essential attributes’ language in social science concept formation.