Source : Webster's Revised Unabridged Dictionary (1913)

Cockhorse \Cock"horse`\, n.
   1. A child's rocking-horse.

            Ride a cockhorse to Banbury cross.    --Mother
                                                  Goose.

   2. A high or tall horse. [R.]

Cockhorse \Cock"horse`\, a.
   1. Lifted up, as one is on a tall horse.

   2. Lofty in feeling; exultant; proud; upstart.

            Our painted fools and cockhorse peasantry.
                                                  --Marlowe.

Source : WordNet®

cockhorse
     n : anything used as a toy horse (such as a rocking horse or one
         knee of an adult)