Green’s Dictionary of Slang

earth-pu n.

also erth-pu
[backsl.; earth n.1 ]

three-up, a street gambling game based on coin-tossing.

[UK]Hotten Dict. of Modern Sl. etc. 126: erth-pu, three-up, — a street game.
[UK]Hotten Sl. Dict. [as cit. 1859].
[UK]Sl. Dict.