Meaning

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

originEtymology tree Proto-Indo-European *h₂erkʷ- Proto-Indo-European *h₂erkʷos Proto-Italic *arkuos Latin arcusder. English arc- Proto-Indo-European *ḱe? Proto-Indo-European *ḱóm Proto-Italic *kom Proto-Italic *kom- Latin con- Latin co-der. English co- Proto-Indo-European *sinos Proto-Italic *sinus Latin sinusbor. English sine English cosine English arccosine From arc- + cosine.

Etymology from Wiktionary, CC BY-SA 3.0