ammonite

Extinct marine cephalopod mollusc of the order Ammonoidea, related to the modern nautilus. The shell was curled in a plane spiral and made up of numerous gas-filled chambers, the outermost containing the body of the animal. Many species flourished between 200 million and 65 million years ago, ranging in size from that of a small coin to 2 m/6 ft across.

Ammonites occur abundantly as fossils, and their rapid evolutionary changes make them important index fossils for correlating and dating rocks.

Ammonite

Member of an ancient Semitic people, mentioned in the Old Testament or Jewish Bible, who lived northwest of the Dead Sea. Their capital was Amman, in present-day Jordan. They worshipped the god Moloch, to whom they offered human sacrifices. They were frequently at war with the Israelites.