trunk vs body part

trunk and body part both are nouns.

Word	Noun	Adjective	Verb	Adverb
trunk	Yes	No	No	No
body part	Yes	No	No	No

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

trunk (noun)	body part (noun)
a long flexible snout as of an elephant	any part of an organism such as an organ or extremity
luggage consisting of a large strong case used when traveling or for storage
compartment in an automobile that carries luggage or shopping or tools
the body excluding the head and neck and limbs
the main stem of a tree; usually covered with bark; the bole is usually the part that is commercially useful for lumber