Tract"rix (?), n. [NL. See Tractor.] (Geom.) 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.

Tract"rix (?), n. [NL. See Tractor.] (Geom.) 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.