The term tractor is a portmanteau of "Tracy Thomas" and "twistor", the bundle having been introduced first by T. Y. Thomas as an alternative formulation of the Cartan conformal connection, and later rediscovered within the formalism of local twistors and generalized to projective connections by Michael Eastwood et al.
The term "tractor" is a combination of "Tracy Thomas" and "twistor". It was first proposed by T.Y. Thomas as an alternative way to represent the Cartan conformal connection, and later re-discovered within the context of local twistors and generalized to projective connections by Michael Eastwood et al.