Source : Webster's Revised Unabridged Dictionary (1913)

Vaquero \Va*que"ro\, n. [Sp., cowherd, fr. vaca a cow, L. vacca.
   Cf. {Vacher}.]
   One who has charge of cattle, horses, etc.; a herdsman.
   [Southwestern U. S.]

Source : WordNet®

vaquero
     n : local names for a cowboy (`vaquero' is used especially in
         southwestern and central Texas and `buckaroo' is used
         especially in California) [syn: {buckaroo}, {buckeroo}]