Green’s Dictionary of Slang

1. a widow’s peak.

c.1698		B.E. Dict. Canting Crew n.p.: bill of sale a Bandore, or Widow’s Peak.
1725		New Canting Dict.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict.

2. a widow’s weeds.

1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1812–82		B.M. Carew Life and Adventures.
1846		Swell’s Night Guide 113/2: Bill of sale, widow’s weeds, house to let.
1859		Matsell Vocabulum.
1868		J.D. McCabe Secrets of the Great City 359: The Detectives’ Manual gives a glossary of this language, from which we take the following specimens [...] Bill of sale. – A widow’s weeds.
1881		Trumble Sl. Dict. (1890).