A holy war is a term used to describe a conflict that is fought for religious reasons. Jehad, CRUSADE, JIHAD, and CAMPAIGN are all words used to refer to a holy war. Jehad is an Arabic word meaning 'STRUGGLE' or 'STRIVING'. CRUSADE is a term used to describe a series of religious wars fought by Christians in the Middle Ages. JIHAD is an Arabic word meaning 'STRUGGLE' or 'STRIVING' and is often used to refer to a holy war. CAMPAIGN is a term used to describe a military operation that is part of a larger conflict.