Source : Webster's Revised Unabridged Dictionary (1913)

Cockspur \Cock"spur\, n. (Bot.)
   A variety of {Crat[ae]gus}, or hawthorn ({C. Crus-galli}),
   having long, straight thorns; -- called also {Cockspur
   thorn}.

Source : WordNet®

cockspur thorn
     n : eastern United States hawthorn with long straight thorns
         [syn: {cockspur hawthorn}, {Crataegus crus-galli}]