flower vs ray flower

flower and ray flower both are nouns.

Word	Noun	Adjective	Verb	Adverb
flower	Yes	No	Yes	No
ray flower	Yes	No	No	No

As nouns, ray flower is a hyponym of flower; that is, ray flower is a word with a more specific, narrower meaning than flower:

flower: reproductive organ of angiosperm plants especially one having showy or colorful parts
ray flower: small flower with a flat strap-shaped corolla usually occupying the peripheral rings of a composite flower

Other hyponyms of flower include floret, floweret, apetalous flower, inflorescence, ray floret, bud, chrysanthemum.

flower (noun)	ray flower (noun)
a plant cultivated for its blooms or blossoms	small flower with a flat strap-shaped corolla usually occupying the peripheral rings of a composite flower
reproductive organ of angiosperm plants especially one having showy or colorful parts
the period of greatest prosperity or productivity

flower (verb)	ray flower (verb)
produce or yield flowers