binormal

[ bahy-nawr-muh l, bahy-nawr- ]
/ ˈbaɪˌnɔr məl, baɪˈnɔr- /

noun Geometry.

the normal to a curve, lying perpendicular to the osculating plane at a given point on the curve.

Origin of binormal

First recorded in 1840–50; bi-1 + normal
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019