call box vs compartment

call box and compartment both are nouns.

Word	Noun	Adjective	Verb	Adverb
call box	Yes	No	No	No
compartment	Yes	No	No	No

As nouns, compartment is a hypernym of call box; that is, compartment is a word with a broader meaning than call box:

call box: a numbered compartment in a post office where mail is put to be called for
compartment: a space into which an area is subdivided

call box (noun)	compartment (noun)
booth for using a telephone	a partitioned section, chamber, or separate room within a larger enclosed area
a numbered compartment in a post office where mail is put to be called for	a space into which an area is subdivided