shoulder blade vs scapula

shoulder blade and scapula both are nouns.

Word	Noun	Adjective	Verb	Adverb
shoulder blade	Yes	No	No	No
scapula	Yes	No	No	No

As nouns, shoulder blade and scapula are synonyms defined as:

shoulder blade and scapula: either of two flat triangular bones one on each side of the shoulder in human beings

Other synonyms of shoulder blade include shoulder bone.

shoulder blade (noun)	scapula (noun)
either of two flat triangular bones one on each side of the shoulder in human beings	either of two flat triangular bones one on each side of the shoulder in human beings