What is Collar ?
Collar is (noun) 1. the part of a piece of clothing which goes round your neck I can’t do up the top button on my shirt – the collar’s too tight. She turned up her coat collar because the wind was cold. He has a winter coat with a fur collar. to get hot under the collar to get angry or worried about something 2. a leather ring round the neck of a dog or cat The cat has a collar with her name and address on it.(verb) to catch someone, especially in order to talk to them (slang) I managed to collar him as he was leaving the hotel.
source: Easier English, Student Dictionary Upper Intermediate Level