Read the excerpt from the passage and the dictionary entry. (6) Usually, at the beginning of school, there was a great uproar which could be heard in the street, desks opening and
closing, lessons repeated aloud in unison, with our ears stuffed in order to learn quicker, and the teacher's stout [shout]:
(7) "A little more quieti"
unison (yu na san, -zan)

1. coincidence in pitch of two or more musical tones, voices, etc.
2. the performance of musical parts at the same pitch or at the octave.
3. a sounding together in octaves, esp. of male and female voices or of higher and lower instruments of the same class,
4. a state or process in which all members or elements behave in the same way at the same time.
Which dictionary definition matches the use of the word unison in the passage?
Def 1
Def 2
Def 3
Def 4