Jihad and crusade differed fundamentally in religious warrant and scope.

Evidence

The jiha¯d was a sacred mission enjoined by scripture and incorporated in the holy law, to continue until all the world was open to the light of Islam. The crusade was a human enterprise, not enjoined—some might rather say forbidden—by Christian scripture, and undertaken for a limited purpose, to defend, or, where lost, to recover, Christian territories. — Bernard Lewis, From Babel to Dragomans, 677

Categorization

• XREF: Feeds the Islam-West cluster: complicates the common framing that sees both as symmetrical holy wars — useful nuance against Said-adjacent accounts that flatten all such conflicts into equivalent crusades.
• DEFINE: Sharpens the technical distinction between jihad and crusade for any argument that conflates them.