Green’s Dictionary of Slang

gan n.

also ganns, gans
[? Welsh geneu, Cornish ganau, mouth; Scot. gane or ganne, mouth, orig. of a fish; itself linked to Norw. gan, a fish-gill]

(UK Und.) the mouth; in pl., the lips; occas. the throat.

[UK]R. Copland Hye way to the Spyttel House Eiii: Cyarum by salmon and thou shalt pek my iere / In thy gan for my watch it is nace gere.
[UK]Harman Caveat for Common Cursetours in Viles & Furnivall (1907) 82: gan, a mouth.
[UK]Groundworke of Conny-catching [as cit. c.1566].
[UK]Dekker Lanthorne and Candle-Light Ch. 1: [as cit. c.1535].
[UK]Rowlands Martin Mark-all 43: A gere peck in thy gan.
[UK]R. Brome Jovial Crew II i: This Bowse is better than Rum-bowse, / It sets the Gan a-gigling.
[Ire]Head Eng. Rogue I 49: Gan, A Lip.
[Ire] ‘The Rogues . . . praise of his Stroling Mort’ in Head Canting Academy (1674) 19: White thy fambles, red thy gan, / And thy quarrons dainty is.
[UK]R. Holme Academy of Armory Ch. iii item 68c: Canting Terms used by Beggars, Vagabonds, Cheaters, Cripples and Bedlams. [...] Gan, a Mouth.
[UK]B.E. Dict. Canting Crew n.p.: Ganns c. the Lipps.
[UK]J. Shirley Triumph of Wit 198: [as cit. 1674].
Vain Dreamer (in Dodsley 1826) 46: Her gans were like to coral red, / A thousand times I kissed ’em.
[UK]Bailey Universal Etym. Eng. Dict. n.p.: gan a mouth. [Ibid.] gans the lips.
[UK]Scoundrel’s Dict. 18: Lips – Gans.
[UK]Grose Classical Dict. of the Vulgar Tongue n.p.: gan the mouth or lips (cant).
[UK]G. Andrewes Dict. Sl. and Cant n.p.: Gan the mouth.
[UK]Lex. Balatronicum [as cit. 1785].
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue [as cit. 1785].
[UK]G. Kent Modern Flash Dict. [as cit. 1809].
[UK]Flash Dict. in Sinks of London Laid Open.
[US]Matsell Vocabulum [as cit. 1785].
[US]Trumble Sl. Dict. (1890).
[US]A.J. Pollock Und. Speaks 43/2: Gans, the lips.