The concept was subsequently extended to include those who die during the performance of a godly action (e.g. during al-ḥajj, or while building a mosque), or while fulfilling one's God-given obligation (e.g. during childbirth). It could also include violent death (e.g. in a shipwreck or a storm) when accompanied by islam or trust in God.
Martyrdom is of particular importance in Shīʿa Islam. al-Ḥusain is shāhi shuhadā, king of the martyrs. Ritual participation in his sufferings includes self-flagellation, often of a severe kind, and also the performance of taʿzīya (condolence, expressed through re-enactments of the life and death of al-Ḥusain). It is moderated by ṭaqīya, the concealment of faith under persecution or pressure—perhaps even as an obligation.
The word and the concept of martyrdom were adopted by the Sikhs (though usually transliterated as ‘shaheed’).
"Shahīd." The Concise Oxford Dictionary of World Religions. . Encyclopedia.com. (August 21, 2018). http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/shahid
"Shahīd." The Concise Oxford Dictionary of World Religions. . Retrieved August 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/shahid