china pink vs rainbow pink

china pink and rainbow pink both are nouns.

Word	Noun	Adjective	Verb	Adverb
china pink	Yes	No	No	No
rainbow pink	Yes	No	No	No

As nouns, china pink and rainbow pink are synonyms defined as:

china pink and rainbow pink: Chinese pink with deeply toothed rose-lilac flowers with a purplish eye; usually raised as an annual

Other synonyms of china pink include Dianthus chinensis.

china pink (noun)	rainbow pink (noun)
Chinese pink with deeply toothed rose-lilac flowers with a purplish eye; usually raised as an annual	Chinese pink with deeply toothed rose-lilac flowers with a purplish eye; usually raised as an annual