KEY, or Quay, a long wharf, usually built of stone, by the side of a harbour or river, and having several storehouses for the convenience of lading and discharging merchant ships. It is accordingly furnished with posts and rings, whereby they are secured; together with cranes, capsterns, and other engines, to lift the goods into or out of the vessels which lie alongside.
The verb cajare, in old writers, according to Scaliger, signifies to keep in or restrain; and hence came our term key or quay, the ground where they are made being bound in with planks and posts.