synaesthesia vs sense datum

synaesthesia and sense datum both are nouns.

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

As nouns, sense datum is a hypernym of synaesthesia; that is, sense datum is a word with a broader meaning than synaesthesia:

synaesthesia: a sensation that normally occurs in one sense modality occurs when another modality is stimulated
sense datum: an unelaborated elementary awareness of stimulation

Other hypernyms of synaesthesia include aesthesis, esthesis, sensation, sense experience, sense impression.

synaesthesia (noun)	sense datum (noun)
a sensation that normally occurs in one sense modality occurs when another modality is stimulated	an unelaborated elementary awareness of stimulation