A two-component Complex column Vector. Spinors are used in physics to represent particles with half-integral spin (i.e., Fermions ).
References
Lounesto, P. ``Counterexamples to Theorems Published and Proved in Recent Literature on Clifford Algebras, Spinors,
Spin Groups, and the Exterior Algebra.''
http://www.hit.fi/~lounesto/counterexamples.htm.
Morse, P. M. and Feshbach, H. ``The Lorentz Transformation, Four-Vectors, Spinors.'' §1.7 in
Methods of Theoretical Physics, Part I. New York: McGraw-Hill, pp. 93-107, 1953.