ra.khas describes fastening the breastpiece to the ephod by its rings so that it remains in place.

The attested use describes fastening the breastpiece to the ephod by its rings with a blue cord, with the stated result that the breastpiece is not removed from the ephod.

1. Fastening the breastpiece to the ephod · dominant

   In Exodus 28:28, the Qal imperfect form occurs in the instruction to secure the breastpiece by its rings to the ephod's rings with a blue cord, so that it will not be removed. In Exodus 39:21, the sequential imperfect form occurs in the corresponding action; the APB renders the clause "They bound the breastpiece from its rings to the rings of the ephod."

   Exodus 28:28Exodus 39:21

In the Anselm Project Bible: The APB presents the action as "bind" in Exodus 28:28 and "bound" in Exodus 39:21. These are clause-level renderings rather than definitions.