Sky is a noun. It can be use as a subject.
Rainstorm is a noun. Nouns are people, places, and things.
The word lightning is a noun. It is a flash of light in the sky produced by electricity within a cloud.
The word rainbow is a noun. A rainbow is a multicoloured arch that appears in the sky.
metaphor
part of speech
The part of speech for this particular word is a noun.
what part of speech is beneath
adverb
what part of speech is work
the part of speech sashay is a averb
Did is a verb, and not is an adverb. Didn't is not any part of speech. It's a contraction of did and not.