from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The essence of a particular thing; those qualities that define it and make it unique.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the essence that makes something the kind of thing it is and makes it different from any other
From Medieval Latin haecceitas, thisness, coined by Duns Scotus. (Wiktionary)