The Collaborative International Dictionary of English v.0.48:

Scot \Scot\, n. [Icel. skot; or OF. escot, F. ['e]cot, LL.
   scottum, scotum, from a kindred German word; akin to AS.
   scot, and E. shot, shoot; cf. AS. sce['o]tan to shoot, to
   contribute. See Shoot, and cf. Shot.]
   A portion of money assessed or paid; a tax or contribution; a
   mulct; a fine; a shot.
   [1913 Webster]

   Scot and lot, formerly, a parish assessment laid on
      subjects according to their ability. [Eng.] --Cowell. Now,
      a phrase for obligations of every kind regarded
      collectivelly.
      [1913 Webster]

            Experienced men of the world know very well that it
            is best to pay scot and lot as they go along.
                                                  --Emerson.
      [1913 Webster] Scotal

WordNet (r) 3.0 (2006):

scot and lot
    n 1: obligations of all kinds taken as a whole

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

SCOT AND LOT, Eng. law. The name of a customary contribution, laid upon all
the subjects according to their ability.