birdness en · NOUN
Etymology
From bird + -ness.
Meanings
-
(uncountable) The quality of being a bird.
When we reason about an arbitrary bird, we may conclude that it flies, but we do not alter our concept of birdness to include flight in order to make that conclusion, as the above account implies.
2000, Timothy R. Colburn, Philosophy and Computer Science, page 91:A penguin or a clucking hen logically might satisfy the ascertainable criteria of birdness but remain somehow inapt for excavating focal meanings.
2012, Richard Biernacki, Reinventing Evidence in Social Inquiry: