wreath vs flower arrangement

wreath and flower arrangement both are nouns.

Word	Noun	Adjective	Verb	Adverb
wreath	Yes	No	No	No
flower arrangement	Yes	No	No	No

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

wreath: flower arrangement consisting of a circular band of foliage or flowers for ornamental purposes
flower arrangement: a decorative arrangement of flowers

Other hypernyms of wreath include floral arrangement.

wreath (noun)	flower arrangement (noun)
flower arrangement consisting of a circular band of foliage or flowers for ornamental purposes	a decorative arrangement of flowers