1.
When a number of people ~, each person gives some money so that they can pay for something together. (INFORMAL)
They ~ for the petrol and food...
The brothers ~ a certain amount of money each month to hire a home health aide.
= contribute
PHRASAL VERB: V P, V P n (not pron), also V P with n
2.
If someone chips in during a conversation, they interrupt it in order to say something. (INFORMAL)
‘That’s true,’ chipped in Quaver...
He chipped in before Clements could answer.
PHRASAL VERB: V P with quote, V P