thyrse vs flower cluster

thyrse and flower cluster both are nouns.

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

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

thyrse: a dense flower cluster (as of the lilac or horse chestnut) in which the main axis is racemose and the branches are cymose
flower cluster: an inflorescence consisting of a cluster of flowers

thyrse (noun)	flower cluster (noun)
a dense flower cluster (as of the lilac or horse chestnut) in which the main axis is racemose and the branches are cymose	an inflorescence consisting of a cluster of flowers