Source : Webster's Revised Unabridged Dictionary (1913)

Thrum \Thrum\, v. t. [imp. & p. p. {Thrummed}; p. pr. & vb. n.
   {Thrumming}.]
   1. To furnish with thrums; to insert tufts in; to fringe.

            Are we born to thrum caps or pick straw? --Quarles.

   2. (Naut.) To insert short pieces of rope-yarn or spun yarn
      in; as, to thrum a piece of canvas, or a mat, thus making
      a rough or tufted surface. --Totten.

Source : WordNet®

thrum
     n : a thrumming sound; "he could hear the thrum of a banjo"
     v 1: sound with a monotonous hum [syn: {hum}]
     2: sound the strings of (a string instrument); "strum a guitar"
        [syn: {strum}]
     3: make a rhythmic sound; "Rain drummed against the
        windshield"; "The drums beat all night" [syn: {drum}, {beat}]
     [also: {thrumming}, {thrummed}]

thrumming
     See {thrum}