noun, plural trac·tri·ces [trak-trahy-seez, trak-truh-seez] /trækˈtraɪ siz, ˈtræk trəˌsiz/. Geometry.

a curve whose tangents are all of equal length; the involute of a catenary.

Origin of tractrix

1720–30; < New Latin, equivalent to Latin trac-, variant stem of trahere to draw, pull + -trīx -trix Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019