The story
Formed after tractor, as if from a Latin *tractrīx (from trahō (“to pull”) + -trīx).
Etymology from Wiktionary, CC BY-SA 4.0.
tractrix
Today it means: A curve that satisfies the following property: that segment of the tangent line that lies between the point of tangency and a fixed line has length independent of the point of tangency chosen. Full definition →