It wasnarrated from Abu Hurairah that the Prophet (ﷺ) said:
"What doyou say among yourselves about the martyr?" They said: "The onewho is killed in the cause of Allah." He said: "In that case themartyrs among my nation would be few. Whoever is killed in the causeof Allah is a martyr; whoever dies in the cause of Allah is a martyr;whoever dies of a stomach disease is a martyr; and whoever dies ofthe plague is a martyr."
English reference: Vol. 4, Book 24, Hadith 2804
Arabic reference: Book 24, Hadith 2910