Gray Publique Deposited
A slang term for a halfpenny with both sides alike, and used by sharpers.
Mayhew, in his book London Labour and London Poor, 1851 (i. 199), has the following passage: "I don't like tossing the coster lads; they're the wide-awakes that way. The thieves use 'grays.' They're ha'pennies, either both sides heads or tails."
- Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)