dinnertime vs suppertime

dinnertime and suppertime both are nouns.

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

As nouns, dinnertime and suppertime are synonyms defined as:

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

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