arcus vs arcus senilis

arcus and arcus senilis both are nouns.

Word	Noun	Adjective	Verb	Adverb
arcus	Yes	No	No	No
arcus senilis	Yes	No	No	No

As nouns, arcus and arcus senilis are synonyms defined as:

arcus and arcus senilis: a whitish deposit in the shape of an arc that is sometimes seen in the cornea

arcus (noun)	arcus senilis (noun)
a whitish deposit in the shape of an arc that is sometimes seen in the cornea	a whitish deposit in the shape of an arc that is sometimes seen in the cornea