Ringneck \Ring"neck`\, n.

1. (Zo["o]l.) Any one of several species of small plovers of the genus [AE]gialitis, having a ring around the neck. The ring is black in summer, but becomes brown or gray in winter. The semipalmated plover ([AE]. semipalmata) and the piping plover ([AE]. meloda) are common North American species. Called also ring plover, and ring-necked plover.

2. (Zo["o]l.) The ring-necked duck.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Ring-necked \Ring"-necked`\, a. (Zo["o]l.) Having a well defined ring of color around the neck.

Ring-necked duck (Zool.), 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. Called also ring-neck, ring-necked blackhead, ringbill, tufted duck, and black jack.

Source: Webster's Revised Unabridged Dictionary (1913)
 

2. (Zo["o]l.) A scaup duck. See below.

Scaup duck (Zo["o]l.), any one of several species of northern ducks of the genus Aythya, or Fuligula. The adult males are, in large part, black. The three North American species are: the greater scaup duck (Aythya marila, var. nearctica), called also broadbill, bluebill, blackhead, flock duck, flocking fowl, and raft duck; the lesser scaup duck (A. affinis), called also little bluebill, river broadbill, and shuffler; the tufted, or ring-necked, scaup duck (A. collaris), called also black jack, ringneck, ringbill, ringbill shuffler, etc. See Illust.. of Ring-necked duck, under Ring-necked. The common European scaup, or mussel, duck (A. marila), closely resembles the American variety.

Source: Webster's Revised Unabridged Dictionary (1913)