from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A marine fossil consisting of a hard anatomical structure like a curved shelly plate, once part of the body of an ammonite.
from the GNU version of the Collaborative International Dictionary of English
- n. A shelly plate found in the terminal chambers of ammonite shells. Some authors consider them to be jaws; others, opercula.
from The Century Dictionary and Cyclopedia
- n. In Cephalopoda, a plate formed of a shelly substance, found in the terminal chamber of certain fossil mollusks, as ammonites, and regarded by some as an operculum.
Sorry, no etymologies found.