os trapezium vs trapezium

os trapezium and trapezium both are nouns.

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

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

os trapezium and trapezium: 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 bone.

os trapezium (noun)	trapezium (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
	a quadrilateral with no parallel sides