inverse cosine vs arc cosine

inverse cosine and arc cosine both are nouns.

Word	Noun	Adjective	Verb	Adverb
inverse cosine	Yes	No	No	No
arc cosine	Yes	No	No	No

As nouns, inverse cosine and arc cosine are synonyms defined as:

inverse cosine and arc cosine: the inverse function of the cosine; the angle that has a cosine equal to a given number

Other synonyms of inverse cosine include arccos, arccosine.

inverse cosine (noun)	arc cosine (noun)
the inverse function of the cosine; the angle that has a cosine equal to a given number	the inverse function of the cosine; the angle that has a cosine equal to a given number