Source : Webster's Revised Unabridged Dictionary (1913)

Calmness \Calm"ness\, n.
   The state of quality of being calm; quietness; tranquillity;
   self-repose.

         The gentle calmness of the flood.        --Denham.

         Hes calmness was the repose of conscious power. --E.
                                                  Everett.

   Syn: Quietness; quietude; stillness; tranquillity; serenity;
        repose; composure; sedateness; placidity.

Source : WordNet®

calmness
     n 1: steadiness of mind under stress; "he accepted their problems
          with composure and she with equanimity" [syn: {composure},
           {calm}, {equanimity}] [ant: {discomposure}]
     2: an absence of strong winds or rain
     3: a feeling of calm; an absence of agitation or excitement
        [ant: {agitation}]