\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}.