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]

Moby Thesaurus II by Grady Ward, 1.0:

58 Moby Thesaurus words for "prehension":
   abduction, apprehension, arrest, arrestation, bottling up, capture,
   catch, catching, clairvoyance, collaring, command, comprehension,
   conception, conceptualization, corking up, coup, dragnet,
   forcible seizure, foreknowledge, grab, grabbing, grasp, grip, hold,
   holding, holding in, ideation, inhibition, intellection,
   intelligence, keeping, kidnapping, locking in, maintenance,
   mastery, mental grasp, nabbing, picking up, power grab,
   precognition, preservation, repression, retainment, retention,
   retentiveness, retentivity, running in, savvy, seizure,
   seizure of power, snatch, snatching, suppression, taking in,
   taking into custody, tenacity, understanding, wisdom



Bouvier's Law Dictionary, Revised 6th Ed (1856):

PREHENSION. The lawful taking of a thing with an intent to, assert a right
in it.