Nematode is a term used to describe a group of worms that are round in shape and have a long, thin body. This group includes the ROUNDWORM, EELWORM, WORM, THREADWORM, and pinworm. All of these worms are characterized by their cylindrical bodies and lack of segmentation. They are found in a variety of habitats, including soil, water, and even inside other animals. Nematodes are important to the environment as they help to break down organic matter and provide food for other organisms.