Full Idea
The definition is an account, and every account has its parts, and there is an isomorphism between the relation of the account to the entity that it concerns and the relation of a part of the account to a part of the entity.
Gist of Idea
The parts of a definition are isomorphic to the parts of the entity
Source
Aristotle (Metaphysics [c.324 BCE], 1034b20)
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.201
A Reaction
This makes a definition sound like a catalogue of parts, which is likely to miss something important, such as the overall form, or the function. Aristotle has much more to say on the subject of definition. Cf. Russell's congruence view of truth.