The Collaborative International Dictionary of English v.0.48:

Prohibition \Pro`hi*bi"tion\, n.
   The period of 1920 to 1932 in the United States, during which
   sale of alcoholic beverages were forbidden by the
   consitution.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Prohibition \Pro`hi*bi"tion\, n. [L. prohibitio: cf. F.
   prohibition.]
   1. The act of prohibiting; a declaration or injunction
      forbidding some action; interdict.
      [1913 Webster]

            The law of God, in the ten commandments, consists
            mostly of prohibitions.               --Tillotson.
      [1913 Webster]

   2. Specifically, the forbidding by law of the sale of
      alcoholic liquors as beverages.
      [1913 Webster]

   Writ of prohibition (Law), a writ issued by a superior
      tribunal, directed to an inferior court, commanding the
      latter to cease from the prosecution of a suit depending
      before it. --Blackstone.
      [1913 Webster]

   Note: By ellipsis, prohibition is used for the writ itself.
         [1913 Webster]

WordNet (r) 3.0 (2006):

prohibition
    n 1: a law forbidding the sale of alcoholic beverages; "in 1920
         the 18th amendment to the Constitution established
         prohibition in the US"
    2: a decree that prohibits something [syn: prohibition, ban,
       proscription]
    3: the period from 1920 to 1933 when the sale of alcoholic
       beverages was prohibited in the United States by a
       constitutional amendment [syn: prohibition, prohibition
       era]
    4: refusal to approve or assent to
    5: the action of prohibiting or inhibiting or forbidding (or an
       instance thereof); "they were restrained by a prohibition in
       their charter"; "a medical inhibition of alcoholic
       beverages"; "he ignored his parents' forbiddance" [syn:
       prohibition, inhibition, forbiddance]