tractrix

 
Pronunciation: /ˈtraktrɪks/

noun (plural tractrices /-trɪsiːz/)

Geometry
  • a curve whose tangents all intercept the x-axis at the same distance from the point of contact, being the involute of a catenary.
  • one of a class of curves similarly traced by one end of a rigid rod, whose other end moves along a fixed line or curve.

Origin:

early 18th century: modern Latin, feminine of late Latin tractor 'that which pulls' (see tractor)