dog collar 
noun informal
A clerical collar.Suffice to say that yesterday saw the start of advent, a fact which was noted by the visiting preacher at our Church yesterday, by the fact that he wore a purple shirt with his dog collar....
- And then he will perform a quick costume change before emerging in his dog collar and cassock to lead the ceremony.
- He also confirmed Aitken's plans to study theology but added: ‘Let's scotch this rumour that he's going to get a dog collar round his neck and go off to the Church.’