os trapezium vs trapezium bone

os trapezium and trapezium bone both are nouns.

Word	Noun	Adjective	Verb	Adverb
os trapezium	Yes	No	No	No
trapezium bone	Yes	No	No	No

As nouns, os trapezium and trapezium bone are synonyms defined as:

os trapezium and trapezium bone: the wrist bone on the thumb side of the hand that articulates with the 1st and 2nd metacarpals

Other synonyms of os trapezium include trapezium.

os trapezium (noun)	trapezium bone (noun)
the wrist bone on the thumb side of the hand that articulates with the 1st and 2nd metacarpals	the wrist bone on the thumb side of the hand that articulates with the 1st and 2nd metacarpals