Thayer's Greek Lexicon

 1. to lay hold of
  1) to lay hold of so as to make one's own, to obtain, attain to,
to make one's own, to take into one's self, appropriate
  2) to seize upon, take possession of
1b1. of evils overtaking one, of the last day overtaking the
wicked with destruction, of a demon about to torment one
1b2. in a good sense, of Christ by his holy power and influence
laying hold of the human mind and will, in order to prompt
and govern it
  3) to detect, catch
  4) to lay hold of with the mind
1d1. to understand, perceive, learn, comprehend