arccosine vs arccos

arccosine and arccos both are nouns.

Word	Noun	Adjective	Verb	Adverb
arccosine	Yes	No	No	No
arccos	Yes	No	No	No

As nouns, arccosine and arccos are synonyms defined as:

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

Other synonyms of arccosine include arc cosine, inverse cosine.

arccosine (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