NOUN (2)

1. prayers proclaiming God's anger against sinners; read in the Church of England on Ash Wednesday;

2. a threat of divine punishment or vengeance;

The Collaborative International Dictionary of English v.0.48:

Commination \Com`mi*na"tion\, n. [L. comminatio, from comminari
   to threaten; com- + minari to threaten: cf. F. commination.]
   1. A threat or threatening; a denunciation of punishment or
      vengeance.
      [1913 Webster]

            With terrible comminations to all them that did
            resist.                               --Foxe.
      [1913 Webster]

            Those thunders of commination.        --I. Taylor.
      [1913 Webster]

   2. An office in the liturgy of the Church of England, used on
      Ash Wednesday, containing a recital of God's anger and
      judgments against sinners.
      [1913 Webster]

WordNet (r) 3.0 (2006):

commination
    n 1: prayers proclaiming God's anger against sinners; read in
         the Church of England on Ash Wednesday
    2: a threat of divine punishment or vengeance