- nemertean⇄adj. 1. belonging to the nemerteans.
2. of or having to do with the nemerteans. - nemertean⇄nemertean ornemertian, noun, adjective.
- nemertean⇄noun any one of a phylum of chiefly marine worms, characterized by an elongated, flattened and unsegmented, contractile body, with a complete digestive system, mouth, and anus; ribbon worm. Nemerteans are brightly colored, sometimes growing up to 90 fee