Black powder is a physical mixture of potassium /sodium nitrate, charcoal, and sulfur that is used as a propellant powder in muzzleloading and antique guns.

Black powder is the original gun propellant powder.

related:

• gunpowder
• smokeless powder

Footnotes / Sources:

“Glossary ⇒.” Sporting Arms and Ammunition Manufacturers’ Institute. Ed. SAAMI’s Technical Committee. Web. 15-18 Jan. 2011.