Source : Webster's Revised Unabridged Dictionary (1913)

Round-arm \Round"-arm`\, a. (Cricket)
   Applied to the method delivering the ball in bowling, by
   swinging the arm horizontally. --R. A. Proctor.

Source : WordNet®

round-arm
     adj : with the arm swung round at shoulder height; "round-arm
           bowling"
     adv : with an outward or horizontal swing of the arm; "he hit the
           ball round-arm"