noun
triggering explosive; initiating explosive; primary explosive
Technical term for an explosive used to detonate a larger charge; common in military, demolition, and pyrotechnic contexts.
起爆薬は雷管に使われる。
Triggering explosives are used in detonators.
この起爆薬は衝撃に敏感だ。
This initiating explosive is sensitive to impact.
雷管 is the detonator device that often contains 起爆薬; 起爆薬 is the chemical substance itself.
Compound of 起爆 (きばく, 'detonation') and 薬 (やく, 'chemical agent, drug'). The exact historical derivation is uncertain, but the term follows standard Sino-Japanese word formation patterns for technical vocabulary.