Verb (5-dan, う, intransitive)
1. to come together; to merge; to unite; to meet
俺と視線が合った。Our eyes met.
2. to fit; to match; to suit; to agree with; to be correct
うん、ここで合ってるはずだ。Yeah, this should be the right place.
3. to be profitable; to be equitable
Auxiliary verb (5-dan, う)
4. to do ... to each other; to do ... together
after the -masu stem of a verb
そう言って、二人で笑い合った。Saying that, the two of them laughed together.