fourable board

fourable board

[′fȯr·ə·bəl ‚bȯrd]
(petroleum engineering)
A platform installed in an oil derrick at an elevation of 80-120 feet (24-37 meters) above the derrick floor to support the derrick operator while pipe is being raised or lowered.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.