<zoology> Having a well defined ring of colour around the neck.

<zoology> Ring-necked duck, an American scaup duck (Aythya collaris). The head, neck, and breast of the adult male are black, and a narrow, but conspicuous, red ring encircles the neck. This ring is absent in the female.

Synonyms: ring-neck, ring-necked blackhead, ringbill, tufted duck, and black jack.

(01 Mar 1998)