while vs hot spell

while and hot spell both are nouns.

Word	Noun	Adjective	Verb	Adverb
while	Yes	No	No	No
hot spell	Yes	No	No	No

As nouns, hot spell is a hyponym of while; that is, hot spell is a word with a more specific, narrower meaning than while:

while: a period of indeterminate length (usually short) marked by some action or condition
hot spell: a spell of hot weather

Other hyponyms of while include cold snap, cold spell, snap.

while (noun)	hot spell (noun)
a period of indeterminate length (usually short) marked by some action or condition	a spell of hot weather