Green’s Dictionary of Slang

1. a day.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.

2. (UK und.) a threepenny bit [= tray n.¹ (4)].

1935

Thieves Slang ms list from District Police Training Centre, Ryton-on-Dunsmore, Warwicks 6: Load of hay: Threepenny piece.