thorax vs prothorax

thorax and prothorax both are nouns.

Word	Noun	Adjective	Verb	Adverb
thorax	Yes	No	No	No
prothorax	Yes	No	No	No

As nouns, prothorax is a hyponym of thorax; that is, prothorax is a word with a more specific, narrower meaning than thorax:

thorax: part of an insect's body that bears the wings and legs
prothorax: the anterior part of an insect's thorax; bears the first pair of legs

thorax (noun)	prothorax (noun)
part of an insect's body that bears the wings and legs	the anterior part of an insect's thorax; bears the first pair of legs
the part of the human torso between the neck and the diaphragm or the corresponding part in other vertebrates
the middle region of the body of an arthropod between the head and the abdomen