The Collaborative International Dictionary of English v.0.48:

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.
         [Webster 1913 Suppl.]