nautiloid

noun

1. a mollusk of the subclass Nautiloidea, including nautiluses and many fossil species that were abundant in the Ordovician and Silurian periods.

adjective

2. noting or pertaining to a nautiloid.

noun

1. any mollusc of the Nautiloidea, a group of cephalopods that includes the pearly nautilus and many extinct forms

adjective

2. of, relating to, or belonging to the Nautiloidea

1. Any of various cephalopod mollusks of the subclass Nautiloidea, having a straight or coiled shell divided internally into a series of chambers of increasing size connected by a central tube. The nautiloids include the modern nautiluses as well as numerous extinct species dating back as far as the Cambrian Period.