suppertime vs dinnertime

suppertime and dinnertime both are nouns.

Word	Noun	Adjective	Verb	Adverb
suppertime	Yes	No	No	No
dinnertime	Yes	No	No	No

As nouns, suppertime and dinnertime are synonyms defined as:

suppertime and dinnertime: the customary or habitual hour for the evening meal

suppertime (noun)	dinnertime (noun)
the customary or habitual hour for the evening meal	the customary or habitual hour for the evening meal