chiton vs tunic

chiton and tunic both are nouns.

Word	Noun	Adjective	Verb	Adverb
chiton	Yes	No	No	No
tunic	Yes	No	No	No

As nouns, tunic is a hypernym of chiton; that is, tunic is a word with a broader meaning than chiton:

chiton: a woolen tunic worn by men and women in ancient Greece
tunic: any of a variety of loose fitting cloaks extending to the hips or knees

chiton (noun)	tunic (noun)
primitive elongated bilaterally symmetrical marine mollusk having a mantle covered with eight calcareous plates	any of a variety of loose fitting cloaks extending to the hips or knees
a woolen tunic worn by men and women in ancient Greece	an enveloping or covering membrane or layer of body tissue