Green’s Dictionary of Slang

1. (UK Und.) a crown piece.

1821		Flash Dict.
1835		G. Kent Modern Flash Dict.
1848		Flash Dict. in Sinks of London Laid Open.

2. (US) $10.

1859		Matsell Vocabulum.
1882		Dly Dispatch (Richmond, VA) 1 Nov. 3/3: ‘Ned’ or ‘dews’ means $10.

3. (drugs) $10 worth of drugs [deuce n.¹ (1), i.e. two $5 bags].

2001

ONDCP Street Terms 7: Dews — $10 worth of drugs.