What does "rood" mean?

Additional senses

1. 2.The fourth part of an acre, or forty square rods. By the rood, by the cross; -- a phrase formerly used in swearing. "No, by the road, not so." Shak. -- Rood beam (Arch.), a beam across the chancel of a church, supporting the road. -- Rood loft (Arch.), a loft or gallery, in a church, on which the rood and its appendagess were set up to view. Gwilt. -- Rood screen (Arch.), a screen, between the choir and the body of the church, over which the rood was placed. Fairholt. -- Rood tower (Arch.), a tower at the intersection of the nave and transept of a church; -- when crowned with a spire it was called also rood steeple. Weale. -- Rood tree, the cross. [Obs.] "Died upon the rood tree." Gower.