Source : Webster's Revised Unabridged Dictionary (1913)

Lull \Lull\, v. t. [imp. & p. p. {Lulled}; p. pr. & vb. n.
   {Lulling}.] [Akin to OD. lullen to sing to sleep, G. lullen,
   Dan. lulle, Sw. lulla; all of imitative origin. Cf. {Loll},
   {Lollard}.]
   To cause to rest by soothing influences; to compose; to calm;
   to soothe; to quiet. `` To lull him soft asleep.'' --Spenser.

         Such sweet compulsion doth in music lie, To lull the
         daughters of necessity.                  --Milton.

Source : WordNet®

lulling
     adj : causing to become tranquil [syn: {calming}, {quietening}]