Oak Leaf Cluster vs decoration

Oak Leaf Cluster and decoration both are nouns.

Word	Noun	Adjective	Verb	Adverb
Oak Leaf Cluster	Yes	No	No	No
decoration	Yes	No	No	No

As nouns, decoration is a hypernym of Oak Leaf Cluster; that is, decoration is a word with a broader meaning than Oak Leaf Cluster:

Oak Leaf Cluster: a United States military decoration consisting of bronze or silver oak leaves and acorns awarded to anyone who has won a given medal before
decoration: an award for winning a championship or commemorating some other event

Other hypernyms of Oak Leaf Cluster include laurel wreath, medal, medallion, palm, ribbon.

Oak Leaf Cluster (noun)	decoration (noun)
a United States military decoration consisting of bronze or silver oak leaves and acorns awarded to anyone who has won a given medal before	the act of decorating something (in the hope of making it more attractive)
	something used to beautify
	an award for winning a championship or commemorating some other event