mask vs masquerade ball

mask and masquerade ball both are nouns.

Word	Noun	Adjective	Verb	Adverb
mask	Yes	No	Yes	No
masquerade ball	Yes	No	No	No

As nouns, masquerade ball is a hyponym of mask; that is, masquerade ball is a word with a more specific, narrower meaning than mask:

Other hyponyms of mask include fancy-dress ball, masked ball.

mask (noun)	masquerade ball (noun)
activity that tries to conceal something	a ball at which guests wear costumes and masks
a covering to disguise or conceal the face
a protective covering worn over the face
a party of guests wearing costumes and masks

mask (verb)	masquerade ball (verb)
put a mask on or cover with a mask
shield from light
cover with a sauce
hide under a false appearance
make unrecognizable