Green’s Dictionary of Slang

dub n.1

[dub v.1 ]

1. a key, a picklock; thus dubs, a bunch of keys.

[UK]B.E. Dict. Canting Crew n.p.: Mill the Gig with a Dub, c. to open the Door with a Pick-lock or false Key.
[UK]J. Hall Memoirs (1714) 12: Dub, a Picklock or Key.
[UK]C. Hitchin Regulator 19: A Dubb, alias Tylt, alias Pick-Lock-Key.
[UK]New Canting Dict.
[UK]Bailey Universal Etym. Eng. Dict.
[UK](con. 1710–25) Tyburn Chronicle II in Groom (1999) xxix: A Dub or Tilt A Pick-lock Key.
[UK]J. Fielding Thieving Detected 9: The second way is with a dub, (a name for a false key).
[UK]G. Parker View of Society II 149: A woman [...] dressed like a servant-maid, with a cream-pot in one hand, and Betty in the other; and a number of young Dubs hanging by her side.
[UK]G. Parker Life’s Painter 153: A bunch of young dubs by her side, which are a bunch of small keys.
[US]H. Tufts Autobiog. (1930) 292: dub a false key.
[Aus]Vaux Vocab. of the Flash Lang.
[US]‘One Who Knows’ Inside Out; or, An Interior View of the N.-Y. State Prison 142: The making of dubs, or skeleton keys.
[UK](con. 1715) W.H. Ainsworth Jack Sheppard (1917) 74: That’s the kinchin as was to try the dub for us.
[UK]J. Lindridge Sixteen-String Jack 206: How my bowman he snivelled away, o, / How he broke off all the dubbs in the whitt, / And chivied the darbies in twain, o.
[US]‘Ned Buntline’ Mysteries and Miseries of N.Y. I 114: ‘Dub.’ A pick-lock or master key.
[US]G. Thompson Anna Mowbray 12: Upon the wall hung every implement used by house breakers in their lawless calling – false and skeleton keys (in flash termed dubs).
[UK]Hotten Dict. Modern Sl., Cant etc. 134: Dubs, a bunch of keys.
[Aus]Crowe Aus. Sl. Dict. 25: Dub, a key.

2. (UK Und.) opening a door with a skeleton key or picklock.

[UK]Hell Upon Earth 3: Some are well-vers’d in the Dub; that is, Robbing Dwelling-Houses, Out-Houses, Ware-Houses, Coach-Houses, or Stables, by picking the Locks thereof.
[UK]C. Hitchin Conduct of Receivers and Thief-Takers 13: Those three young Lads, altho’ they are young, yet they are Boman Prigs, and as such go on the lay call’d the Dub, that enter a House, Shop or Ware-House, with a Pick lock key.
[US] ‘Flash Lang.’ in Confessions of Thomas Mount 19: A dub, opening a door with a false key.

3. a picklock boy.

[UK]A. Smith Lives of Most Notorious Highway-men, etc. (1926) 205: Dub, a picklock boy.

4. a toll collector.

[Aus]Vaux Vocab. of the Flash Lang. in McLachlan (1964) 238: dub at a knapping-jigger: a collector of tolls at a turnpike-gate.
[UK](con. 1737–9) W.H. Ainsworth Rookwood (1857) 268: Turpin treated him as he had done the dub at the knapping jigger.

5. a prison warder.

[UK]W.E. Henley ‘Villon’s Good-Night’ in Farmer Musa Pedestris (1896) 175: For you, you coppers, narks, and dubs, / Who pinched me when upon the snam.

In compounds

dub-lay (n.) [lay n.3 (1)] (UK Und.)

1. picking pockets [given the ety., this may be a misinterpretation by The Tyburn Chronicle’s author – there are no refs. in any other dict.].

[UK](con. 1710–25) Tyburn Chronicle II in Groom (1999) xxvii: The Dub Lay Picking Pockets.
[UK]Whole Art of Thieving.

2. (also dab lay) robbery of a house by picking the lock.

[UK]Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: dub-lay Robbing houses by Picking the Locks.
[UK]Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn).
[UK]Lex. Balatronicum.
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.
[US]Matsell Vocabulum.
[Aus]Crowe Aus. Sl. Dict. 25: Dub lay, robbing, by picking the lock.
[Aus]Argus (Melbourne) 20 Sept. 6/4: The black act, or the dab lay consists of picking the lock.
[UK]H. Baumann Londinismen (2nd edn).
[UK]Farmer & Henley Sl. and Its Analogues.

In phrases

go on the dub (v.)

(UK Und.) to break into a house using a picklock or skeleton key.

[UK]B.E. Dict. Canting Crew n.p.: Going upon the dub c. Breaking a House with Picklocks. [Ibid.] We’ll strike it upon the dub, c. we will rob that Place.
[UK]New Canting Dict. [as cit. c.1698].
[UK]Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
[UK]Grose Classical Dict. of the Vulgar Tongue n.p.: going upon the dub going out to break open or pick the locks of houses.
[UK]Lex. Balatronicum.
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.
[US]‘Ned Buntline’ Mysteries and Miseries of N.Y. I 37: When do you want to go on the dub?