o'jiv. In architecture, an arch or branch of the Gothic vault, which passing diagonally from one angle to another forms a cross with the other arches. The middle where the ogives cross each other, is called the key. The members or moldings of the ogives are called nerves, branches or reins, and the arches which separate the ogives, double arches.

The arch or rib which crosses a Gothic vault diagonally.