Definition of collars:
(n) :
Clothes that encircle the neck.
(n) :
The part of an upper garment (shirt, jacket, etc.) that fits around the neck and throat, especially if sewn from a separate piece of fabric.
(n) :
A decorative band or other fabric around the neckline.
(n) :
A chain worn around the neck.
(n) :
A similar detachable item.
(n) :
A coloured ring round the neck of a bird or mammal.