[ ver-mik-yuh-lahyt ]
/ vərˈmɪk yəˌlaɪt /


any of a group of platy minerals, hydrous silicates of aluminum, magnesium, and iron, that expand markedly on being heated: used in the expanded state for heat insulation and as a plant growth medium.

Nearby words

  1. vermicularly,
  2. vermiculate,
  3. vermiculated,
  4. vermiculation,
  5. vermicule,
  6. vermiculose,
  7. vermiculture,
  8. vermiform,
  9. vermiform appendix,
  10. vermiform process

Origin of vermiculite

An Americanism dating back to 1815–25; vermicul(ar) + -ite1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for vermiculite


/ (vɜːˈmɪkjʊˌlaɪt) /


any of a group of micaceous minerals consisting mainly of hydrated silicate of magnesium, aluminium, and iron: on heating they expand and exfoliate and in this form are used in heat and sound insulation, fireproofing, and as a bedding medium for young plants

Word Origin for vermiculite

C19: from vermicul (ar) + -ite 1

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

Word Origin and History for vermiculite



1814, from Latin vermiculari (from vermiculus, diminutive of vermis; see worm) + -ite.

Online Etymology Dictionary, © 2010 Douglas Harper