weigh in

weigh in  {v.}

1a. To take the weight of; weigh.

The man at the airport counter weighed in our bags and took our plane tickets.

A doctor weighed in the wrestlers.

1b. To have yourself or something that you own weighed. — Often used with "at".

I weighed in at 100 pounds on the scale today.

We took our bags to the airport counter to weigh in.

1c. To have yourself weighed as a boxer or wrestler by a doctor before a match. — Often used with "at".

The champion didn't want to weigh in at more than 160 pounds.

2.  {slang}

To join or interfere in a fight, argument, or discussion.

We told Jack that if we wanted him to weigh in with his opinion we would ask him.

Compare: TAKE PART.