1. n. [Drilling Fluids]

A graduated cup used to take samples and to crudely measure volumes of mud for testing at the rig. A mud cup is used primarily with the Marsh funnel to measure one quart of flow out of the funnel. It is also used as a container for performing simple pilot tests with an electric mixer that clamps onto the top of the cup.

See: barrel equivalent,  Marsh funnel,  pilot test,  pressurized mud balance