1) Anything used as a toy horse 2) Plaything 
• (a.) Lifted up, as one is on a tall horse. • (n.) A child`s rocking-horse. • (a.) Lofty in feeling; exultant; proud; upstart. • (n.) A high or tall horse.
Cock'horse` noun 1. A child's rocking-horse. « Ride a cockhorse to Banbury cross. Mother Goose. » 2. A high or tall horse. [ R.]
noun anything used as a toy horse (such as a rocking horse or one knee of an adult)
a child's rocking horse or hobbyhorse.