Encyclopædia Britannica, First Edition/Abate

ABATE, from abatre, to destroy; a term used by the writers of the common law, both in an active and neutral sense; as, to abate a castle, is to destroy or beat it down; to abate a writ, is, by some exception to render it null and void.

Abate, in the manage, implies the performance of any downward motion properly. Hence a horse is said to abate, or take down his curvets, when he puts both his hind-legs to the ground at once, and observes the same exactness in all the times.