What is "widow monkey"

Widow \Wid"ow\ (w[i^]d"[-o]), n. [OE. widewe, widwe, AS. weoduwe, widuwe, wuduwe; akin to OFries. widwe, OS. widowa, D. weduwe, G. wittwe, witwe, OHG. wituwa, witawa, Goth. widuw[=o], Russ. udova, OIr. fedb, W. gweddw, L. vidua, Skr. vidhav[=a]; and probably to Skr. vidh to be empty, to lack; cf. Gr. "hi`qeos a bachelor. [root]248. Cf. Vidual.] A woman who has lost her husband by death, and has not married again; one living bereaved of a husband. ``A poor widow.''
--Chaucer.

2. (Card Playing) In various games (such as ``hearts''), any extra hand or part of a hand, as one dealt to the table. It may be taken by one of the players under certain circumstances.

Grass widow. See under Grass.

Widow bewitched, a woman separated from her husband; a grass widow. [Colloq.]

Widow-in-mourning (Zo["o]l.), the macavahu.

Widow monkey (Zo["o]l.), a small South American monkey ( Callithrix lugens); -- so called on account of its color, which is black except the dull whitish arms, neck, and face, and a ring of pure white around the face.

Widow's chamber (Eng. Law), in London, the apparel and furniture of the bedchamber of the widow of a freeman, to which she was formerly entitled.

n. A small South American monkey (''Callithrix lugens''), black except for the dull whitish arms, neck, and face, and a ring of pure white around the face.