dry powder

Meanings

1. A powder found in a fire extinguisher that is expelled to smother the fire (in contrast with liquid types of extinguisher).
2. A powder found in an inhaler that delivers a bronchodilator for antiasthmatic or antiemphysemic purposes (indications).
3. Cash (or cash-like securities) kept in reserve in case of need.
4. Used other than figuratively or idiomatically: see dry, powder; especially, gunpowder kept dry to keep it from spoiling before use.

Etymology

The financial sense comes by metaphor from the sense of gunpowder kept dry to allow rapid loading of a firearm, as in the expression keep one's powder dry.