dry powder

(finance) Cash (or cash-like securities) kept in reserve in case of need.

A powder found in a fire extinguisher that is expelled to smother the fire (in contrast with liquid types of extinguisher).

A powder found in an inhaler that delivers a bronchodilator for antiasthmatic or antiemphysemic purposes (indications).

Used other than figuratively or idiomatically: see dry, powder; especially, gunpowder kept dry to keep it from spoiling before use.