four-o'clock family vs family Nyctaginaceae

four-o'clock family and family Nyctaginaceae both are nouns.

Word	Noun	Adjective	Verb	Adverb
four-o'clock family	Yes	No	No	No
family Nyctaginaceae	Yes	No	No	No

As nouns, four-o'clock family and family Nyctaginaceae are synonyms defined as:

four-o'clock family and family Nyctaginaceae: a family of flowering plants of the order Caryophyllales

Other synonyms of four-o'clock family include Allioniaceae, family Allioniaceae, Nyctaginaceae.

four-o'clock family (noun)	family Nyctaginaceae (noun)
a family of flowering plants of the order Caryophyllales	a family of flowering plants of the order Caryophyllales