noun
gunsmoke; smoke of cannon
Refers specifically to smoke produced by artillery or cannon fire. A somewhat literary or historical term; in everyday contexts, 砲火の煙 or 大砲の煙 may be more common.
戦場には砲煙が立ちこめていた。
Gunsmoke hung over the battlefield.
砲煙弾雨の中を兵士たちは進んだ。
The soldiers advanced through the hail of bullets and gunsmoke.
硝煙 is a more general term for gunpowder smoke, often used for small arms as well as artillery. 砲煙 is specifically cannon or artillery smoke.
Compound of 砲 (cannon, artillery) and 煙 (smoke). The reading ほうえん is the standard on'yomi combination.