question time vs time period

question time and time period both are nouns.

Word	Noun	Adjective	Verb	Adverb
question time	Yes	No	No	No
time period	Yes	No	No	No

As nouns, time period is a hypernym of question time; that is, time period is a word with a broader meaning than question time:

question time: a period during a parliamentary session when members of British Parliament may ask questions of the ministers
time period: an amount of time

Other hypernyms of question time include period, period of time.

question time (noun)	time period (noun)
a period during a parliamentary session when members of British Parliament may ask questions of the ministers	an amount of time