drilling mud: Meaning and Definition of

drill'ing mud"

Pronunciation: [key]
  1. a water-based or oil-based suspension of clays pumped into an oil well during drilling in order to seal off porous rock layers, equalize the pressure, cool the bit, and flush out the cuttings. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.