Caterpillar and Worms

Caterpillar noun - A large tracked vehicle that is propelled by two endless metal belts; frequently used for moving earth in construction and farm work.

Worms and caterpillar are semantically related. In some cases you can replace term "Worms" with "Caterpillar", this nouns are similar.

Caterpillar and worms are semantically related. Sometimes you can use "Caterpillar" instead a noun "Worms".