The Collaborative International Dictionary of English v.0.48:

Lull \Lull\ (l[u^]l), v. t. [imp. & p. p. Lulled (l[u^]ld); 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.
   [1913 Webster]

         Such sweet compulsion doth in music lie,
         To lull the daughters of necessity.      --Milton.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lull \Lull\, v. i.
   To become gradually calm; to subside; to cease or abate for a
   time; as, the storm lulls.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lull \Lull\, n.
   1. The power or quality of soothing; that which soothes; a
      lullaby. [R.] --Young.
      [1913 Webster]

   2. A temporary cessation of storm or confusion.
      [1913 Webster]

WordNet (r) 3.0 (2006):

lull
    n 1: a pause during which things are calm or activities are
         diminished; "there was never a letup in the noise" [syn:
         letup, lull]
    2: a period of calm weather; "there was a lull in the storm"
       [syn: lull, quiet]
    v 1: calm by deception; "Don't let yourself be lulled into a
         false state of security"
    2: become quiet or less intensive; "the fighting lulled for a
       moment" [syn: lull, calm down]
    3: make calm or still; "quiet the dragons of worry and fear"
       [syn: calm, calm down, quiet, tranquilize,
       tranquillize, tranquillise, quieten, lull, still]
       [ant: agitate, charge, charge up, commove, excite,
       rouse, turn on]

Moby Thesaurus II by Grady Ward, 1.0:

194 Moby Thesaurus words for "lull":
   abate, abeyance, allay, alleviate, anesthetize, anticyclone,
   appease, assuage, awful silence, balm, becalm, benumb, breach,
   break, breath, breather, breathing place, breathing space,
   breathing spell, breathing time, caesura, calm, calm down,
   calmness, cease, cease-fire, cessation, cigarette break,
   cocktail hour, coffee break, comma, compose, cool, cradle, cushion,
   day off, dead, dead calm, dead of night, deaden, deaden the pain,
   deathlike calm, deathlike silence, delay, die down, diminish,
   doldrums, dope, dormancy, downtime, drop, drug, dulcify, dull,
   dwindle, ease, ease matters, ease off, ebb, enforced respite,
   entrance, even out, fall, fissure, flat calm, foment, gap, gentle,
   give relief, golden silence, half time, half-time intermission,
   halt, happy hour, hesitation, hiatus, hibernation, holiday,
   horse latitudes, hush, hush of night, hypnotize, immobility,
   inaction, inactiveness, inactivity, inaudibility, inertia, interim,
   interlude, intermezzo, intermission, intermittence, interregnum,
   interruption, interval, lacuna, lapse, lay, layoff, lessen, let up,
   letup, lucid stillness, lull to sleep, magnetize, mesmerize,
   mitigate, moderate, molder, mollify, motionlessness, mum,
   narcotize, noiselessness, numb, off-time, oily calm, pacify, pad,
   palliate, pause, peace, peacefulness, plateau, point of repose,
   poultice, pour balm into, pour oil on, put to sleep, put under,
   qualify, quell, quiesce, quiescence, quiet, quiet spell, quieten,
   quietness, quietude, recess, reduce, relief, relieve, remission,
   respite, rest, resting point, rock, rock to sleep, salve, sedate,
   settle, silence, silentness, slacken, slake, smooth, smooth down,
   smooth over, smoothen, soften, solemn silence, soothe,
   soundlessness, spell, stabilize, stand-down, stay, steady, still,
   stillness, stop, stupe, subdue, subside, surcease, suspension,
   tacitness, taciturnity, tea break, temper, time off, time out,
   tomblike silence, trance, tranquilize, tranquillity, truce,
   underactivity, vacation, wane, whisht, windlessness