Bible Dictionaries
Tractrix

Webster's Dictionary

(n.) A curve such that the part of the tangent between the point of tangency and a given straight line is constant; - so called because it was conceived as described by the motion of one end of a tangent line as the other end was drawn along the given line.

Bibliography Information
Webster, Noah. Entry for 'Tractrix'. Noah Webster's American Dictionary. https://www.studylight.org/​dictionaries/​eng/​web/​t/tractrix.html. 1828.