(30) باب الشَّهَادَةُ سَبْعٌ سِوَى الْقَتْلِ
Narrated Abu Huraira:
Allah's Messenger (ﷺ) said, "Five are regarded as martyrs: They are those who die because of plague, Abdominal disease, drowning or a falling building etc., and the martyrs in Allah's Cause."
Reference: Sahih al-Bukhari 2829
In-book reference: Book 56, Hadith 45
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 52, Hadith 82