'Till alarm' definitions:

Definition of 'Till alarm'

From: GCIDE

Till \Till\, n. [Properly, a drawer, from OE. tillen to draw. See Tiller the lever of a rudder.] A drawer. Specifically: (a) A tray or drawer in a chest. (b) A money drawer in a shop or store. [1913 Webster]
Till alarm, a device for sounding an alarm when a money drawer is opened or tampered with. [1913 Webster]