دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: 1. a derrick or crane shaped like the letter A and used to handle heavy loads. 2. an A-shaped openwork structure that is the stationary and supporting component of the mast of a jackknife rig and to which the mast is anchored when it is in an upright or drilling position. 3. the uppermost section of a standard derrick, shaped like the letter A and used as a support in lifting objects such as the crown block to the water table.

n: A kind of "A" frame gin pole, used to elevate heavy object.