Webster's Revised Unabridged Dictionary · 1913

Jihad

Jihad , noun

[Arabic jihād, struggle.]

(Islam) A religious war against infidels or Muslim heretics; also, any bitter war or crusade for a principle or belief.
[Their] courage in war... had not, like that of the Muslim dervishes of the Sudan, or of Muslims anywhere engaged in a jehad, a religious motive and the promise of future bliss behind it. — James Bryce

Also: Jehad