receipts vs box office

receipts and box office both are nouns.

Word	Noun	Adjective	Verb	Adverb
receipts	Yes	No	No	No
box office	Yes	No	No	No

As nouns, box office is a hyponym of receipts; that is, box office is a word with a more specific, narrower meaning than receipts:

Other hyponyms of receipts include gate, average revenue.

receipts (noun)	box office (noun)
the entire amount of income before any deductions are made	the office where tickets of admission are sold
	total admission receipts for an entertainment