0 to interrupt what someone is saying by saying something yourself:
I was just talking to Jan, when Dave cut in (on us/our conversation).
1 to make a sudden sideways movement in order to position your car in front of another car, not leaving a safe distance between the two vehicles:
2 If a machine cuts in, it starts, usually automatically:
3 to interrupt two people who are dancing in order to dance with one of them:
