alma gray, n. — Green’s Dictionary of Slang

alma gray n.

[rhy. sl. = tray n.¹ (1); ‘Little’ Alma Gray was a music-hall star c.1900]

(Aus.) a threepenny piece.

1945		Baker Aus. Lang.
1955		N. Pulliam I Travelled a Lonely Land (1957) 229/1: almagray – a threepenny piece.
2002		Pete’s Aussie Sl. Home Page 🌐 Alma Grey: a trey, threepence (obs.).