lunchtime vs lunch period

lunchtime and lunch period both are nouns.

Word	Noun	Adjective	Verb	Adverb
lunchtime	Yes	No	No	No
lunch period	Yes	No	No	No

As nouns, lunchtime and lunch period are synonyms defined as:

lunchtime and lunch period: the customary or habitual hour for eating lunch

lunchtime (noun)	lunch period (noun)
the customary or habitual hour for eating lunch	the customary or habitual hour for eating lunch