Source : Webster's Revised Unabridged Dictionary (1913)

Wellington boot \Wel"ling*ton boot\ [After the Duke of
   Wellington.]
   A riding boot for men, the front of which came above the
   knee; also, a similar shorter boot worn under the trousers.

Source : WordNet®

Wellington boot
     n : (19th century) a man's high tasseled boot [syn: {Hessian
         boot}, {hessian}, {jackboot}, {Wellington}]