arctangent

noun

arc·​tan·​gent (ˌ)ärk-ˈtan-jənt 

variants or less commonly arc tangent

plural arctangents also arc tangents

: the inverse function of the tangent

if y is the tangent of θ, then θ is the arctangent of y

—abbreviation arctan

Word History

First Known Use

1886, in the meaning defined above