(on a drill rig) the assemblage of drill pipes that link the drill bit to the mechanism that imparts rotary or reciprocating motion.
Origin of drill string
First recorded in 1695–1705
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
(in the oil industry) a pipe made of lengths of steel tubing that is attached to the drilling tool and rotates during drilling to form a bore
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012