'Vermiculite' definitions:

Definition of 'vermiculite'

(from WordNet)
noun
Any of a group of yellow or brown hydrous silicate minerals having a micaceous structure

Definition of 'Vermiculite'

From: GCIDE
  • Vermiculite \Ver*mic"u*lite\, n. [L. vermiculus, dim. of vermis worm.] (Min.) A group of minerals having, a micaceous structure. They are hydrous silicates, derived generally from the alteration of some kind of mica. So called because the scales, when heated, open out into wormlike forms. [1913 Webster] Vermiculose