Cockhorse [noun]

Definition of Cockhorse:

child's model horse

Mr. Flamsteed has come in, and says he left Sir Isaac riding cockhorse upon the nebula, and poring over it as if it were a book.

That conqueror of circumstances will, the dullest soul may begin predicting, return on his cockhorse to favour and authority.

He asked if I should like to ride a-cockhorse there with him.