sense datum vs masking

sense datum and masking both are nouns.

Word	Noun	Adjective	Verb	Adverb
sense datum	Yes	No	No	No
masking	Yes	No	No	No

As nouns, masking is a hyponym of sense datum; that is, masking is a word with a more specific, narrower meaning than sense datum:

sense datum: an unelaborated elementary awareness of stimulation
masking: the blocking of one sensation resulting from the presence of another sensation

sense datum (noun)	masking (noun)
an unelaborated elementary awareness of stimulation	the act of concealing the existence of something by obstructing the view of it
	scenery used to block the audience's view of parts of the stage that should not be seen
	the blocking of one sensation resulting from the presence of another sensation