arc cosine vs arccos

arc cosine and arccos both are nouns.

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

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

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

Other synonyms of arc cosine include arccosine, inverse cosine.

arc cosine (noun)	arccos (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