The Collaborative International Dictionary of English v.0.48:

Random \Ran"dom\, a.
   1. Going at random or by chance; done or made at hazard, or
      without settled direction, aim, or purpose; hazarded
      without previous calculation; left to chance; haphazard;
      as, a random guess.
      [1913 Webster]

            Some random truths he can impart.     --Wordsworth.
      [1913 Webster]

            So sharp a spur to the lazy, and so strong a bridle
            to the random.                        --H. Spencer.
      [1913 Webster]

   2. (Statistics) Of, pertaining to, or resulting from a
      process of selection from a starting set of items, in
      which the probability of selecting any one object in the
      starting set is equal to the probability of selecting any
      other.
      [PJC]

   3. (Construction) of unequal size or shape; made from
      components of unequal size or shape.
      [PJC]

   at random in a manner so that all possible results have an
      equal probability of occurrence; for processes, each
      possible result is counted separately although the same
      type of result may occur more than once .

   Random courses (Masonry), courses of stone of unequal
      thickness.

   Random shot, a shot not directed or aimed toward any
      particular object, or a shot with the muzzle of the gun
      much elevated.

   Random work (Masonry), stonework consisting of stones of
      unequal sizes fitted together, but not in courses nor
      always with flat beds.
      [1913 Webster]