flood vs spread over

flood is a noun but spread over is not a noun.

Word	Noun	Adjective	Verb	Adverb
flood	Yes	No	Yes	No
spread over	No	No	Yes	No

As verbs, spread over is a hypernym of flood; that is, spread over is a word with a broader meaning than flood:

Other hypernyms of flood include cover.

flood (noun)	spread over (noun)
the act of flooding; filling to overflowing
a large flow
light that is a source of artificial illumination having a broad beam; used in photography
the occurrence of incoming water (between a low tide and the following high tide)
the rising of a body of water and its overflowing onto normally dry land
an overwhelming number or amount

flood (verb)	spread over (verb)
cover with liquid, usually water	form a cover over
become filled to overflowing
fill quickly beyond capacity; as with a liquid
supply with an excess of