raceme vs flower cluster

raceme and flower cluster both are nouns.

Word	Noun	Adjective	Verb	Adverb
raceme	Yes	No	No	No
flower cluster	Yes	No	No	No

As nouns, flower cluster is a hypernym of raceme; that is, flower cluster is a word with a broader meaning than raceme:

raceme: usually elongate cluster of flowers along the main stem in which the flowers at the base open first
flower cluster: an inflorescence consisting of a cluster of flowers

raceme (noun)	flower cluster (noun)
usually elongate cluster of flowers along the main stem in which the flowers at the base open first	an inflorescence consisting of a cluster of flowers