The Collaborative International Dictionary of English v.0.48:

Prehension \Pre*hen"sion\, n. [L. prehensio; cf. F.
   pr['e]hension. See Prehensile.]
   The act of taking hold, seizing, or grasping, as with the
   hand or other member.
   [1913 Webster]

WordNet (r) 3.0 (2006):

prehension
    n 1: the act of gripping something firmly with the hands (or the
         tentacles) [syn: grasping, taking hold, seizing,
         prehension]