Source : Webster's Revised Unabridged Dictionary (1913)

Thomsonite \Thom"son*ite\, n. [From R. D. Thomson, of Glasgow.]
   (Min.)
   A zeolitic mineral, occurring generally in masses of a
   radiated structure. It is a hydrous silicate of aluminia,
   lime, and soda. Called also {mesole}, and {comptonite}.