Source : Webster's Revised Unabridged Dictionary (1913)

Thigmotaxis \Thig`mo*tax"is\, n. [NL., fr. Gr. ? touch + ? an
   arranging.] (Physiol.)
   The property possessed by living protoplasm of contracting,
   and thus moving, when touched by a solid or fluid substance.

   Note: When the movement is away from the touching body, it is
         {negative thigmotaxis}; when towards it, {positive
         thigmotaxis}.