Source : Webster's Revised Unabridged Dictionary (1913)

Squall \Squall\, n. [Cf. Sw. sqval an impetuous running of
   water, sqvalregn a violent shower of rain, sqala to stream,
   to gush.]
   A sudden violent gust of wind often attended with rain or
   snow.

         The gray skirts of a lifting squall.     --Tennyson.

   {Black squall}, a squall attended with dark, heavy clouds.

   {Thick squall}, a black squall accompanied by rain, hail,
      sleet, or snow. --Totten.

   {White squall}, a squall which comes unexpectedly, without
      being marked in its approach by the clouds. --Totten.