fire drill vs practice session

fire drill and practice session both are nouns.

Word	Noun	Adjective	Verb	Adverb
fire drill	Yes	No	No	No
practice session	Yes	No	No	No

As nouns, practice session is a hypernym of fire drill; that is, practice session is a word with a broader meaning than fire drill:

fire drill: an exercise intended to train people in duties and escape procedures to be followed in case of fire
practice session: systematic training by multiple repetitions

Other hypernyms of fire drill include drill, exercise, practice, recitation.

fire drill (noun)	practice session (noun)
an exercise intended to train people in duties and escape procedures to be followed in case of fire	systematic training by multiple repetitions