[dih-leyt-nt, dahy-]
  1. dilating; expanding.
  2. Physical Chemistry. exhibiting an increase in volume on being changed in shape, owing to a wider spacing between particles.
  3. Petrology. (of rock) exhibiting an increase in volume owing to rearrangement and recrystallization of constituent grains.

Origin of dilatant

1835–45; < Latin dīlātant- (stem of dīlātāns), present participle of dīlātāre to dilate; see -ant
Related formsdi·lat·an·cy, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for dilatancy


  1. a phenomenon caused by the nature of the stacking or fitting together of particles or granules in a heterogeneous system, such as the solidification of certain sols under pressure, and the thixotropy of certain gels


  1. tending to dilate; dilating
  2. physics of, concerned with, or exhibiting dilatancy
  1. something, such as a catheter, that causes dilation
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