spurious wing vs alula

spurious wing and alula both are nouns.

Word	Noun	Adjective	Verb	Adverb
spurious wing	Yes	No	No	No
alula	Yes	No	No	No

As nouns, spurious wing and alula are synonyms defined as:

spurious wing and alula: tuft of small stiff feathers on the first digit of a bird's wing

Other synonyms of spurious wing include bastard wing.

spurious wing (noun)	alula (noun)
tuft of small stiff feathers on the first digit of a bird's wing	tuft of small stiff feathers on the first digit of a bird's wing
	scalelike structure between the base of the wing and the halter of a two-winged fly