interstice vs complex body part

interstice and complex body part both are nouns.

Word	Noun	Adjective	Verb	Adverb
interstice	Yes	No	No	No
complex body part	Yes	No	No	No

As nouns, complex body part is a hypernym of interstice; that is, complex body part is a word with a broader meaning than interstice:

interstice: a small structural space between tissues or parts of an organ
complex body part: a particular complex anatomical part of a living thing and its construction and arrangement

Other hypernyms of interstice include anatomical structure, bodily structure, body structure, structure.

interstice (noun)	complex body part (noun)
small opening between things	a particular complex anatomical part of a living thing and its construction and arrangement
a small structural space between tissues or parts of an organ