An explosive train component which can be activated by either a nonexplosive impulse or the action of a primer and is capable of reliably initiating high order detonation in a subsequent high explosive component of the train. When activated by a non-explosive impulse, a detonator includes the function of a primer.

In general, detonators are classified in accordance with the method of initiation such as percussion, stab, electric, friction, flash chemical, etc. A cap or capsule of sensitive explosive material used to initiate a charge of high explosives. Any device containing any initiating or primary explosive that is used for initiating detonation.

A commercial or may not contain more than 10g of total explosives by weight, excluding ignition or delay charges. The term includes, but is not limited to electric blasting caps of instantaneous and delay types, blasting caps for use with safety uses, detonating cord delay connectors, and nonelectric instantaneous and delay blasting caps that use detonating cord, shock tube, or any other replacement for electric legwires.

Detonators should not be confused with a fire work igniter, or squib, a detonator is used to initiate high explosives. As such, detonators are security attractive items and their possession is controlled in many countries.