The Collaborative International Dictionary of English v.0.48:

Tumble \Tum"ble\, n.
   Act of tumbling, or rolling over; a fall.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tumble \Tum"ble\ (t[u^]m"b'l), v. i. [imp. & p. p. Tumbled
   (t[u^]m"b'ld); p. pr. & vb. n. Tumbling (t[u^]m"bl[i^]ng).]
   [OE. tumblen, AS. tumbian to turn heels over head, to dance
   violently; akin to D. tuimelen to fall, Sw. tumla, Dan.
   tumle, Icel. tumba; and cf. G. taumeln to reel, to stagger.]
   1. To roll over, or to and fro; to throw one's self about;
      as, a person in pain tumbles and tosses.
      [1913 Webster]

   2. To roll down; to fall suddenly and violently; to be
      precipitated; as, to tumble from a scaffold.
      [1913 Webster]

            He who tumbles from a tower surely has a greater
            blow than he who slides from a molehill. --South.
      [1913 Webster]

   3. To play tricks by various movements and contortions of the
      body; to perform the feats of an acrobat. --Rowe.
      [1913 Webster]

   To tumble home (Naut.), to incline inward, as the sides of
      a vessel, above the bends or extreme breadth; -- used esp.
      in the phrase tumbling home. Cf. Wall-sided.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tumble \Tum"ble\, v. t.
   1. To turn over; to turn or throw about, as for examination
      or search; to roll or move in a rough, coarse, or
      unceremonious manner; to throw down or headlong; to
      precipitate; -- sometimes with over, about, etc.; as, to
      tumble books or papers.
      [1913 Webster]

   2. To disturb; to rumple; as, to tumble a bed.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tumble
    n 1: an acrobatic feat of rolling or turning end over end
    2: a sudden drop from an upright position; "he had a nasty spill
       on the ice" [syn: spill, tumble, fall]
    v 1: fall down, as if collapsing; "The tower of the World Trade
         Center tumbled after the plane hit it" [syn: tumble,
         topple]
    2: cause to topple or tumble by pushing [syn: topple,
       tumble, tip]
    3: roll over and over, back and forth
    4: fly around; "The clothes tumbled in the dryer"; "rising smoke
       whirled in the air" [syn: whirl, tumble, whirl around]
    5: fall apart; "the building crumbled after the explosion";
       "Negotiations broke down" [syn: crumble, crumple,
       tumble, break down, collapse]
    6: throw together in a confused mass; "They tumbled the teams
       with no apparent pattern"
    7: understand, usually after some initial difficulty; "She
       didn't know what her classmates were plotting but finally
       caught on" [syn: catch on, get wise, get onto,
       tumble, latch on, cotton on, twig, get it]
    8: fall suddenly and sharply; "Prices tumbled after the
       devaluation of the currency"
    9: put clothes in a tumbling barrel, where they are whirled
       about in hot air, usually with the purpose of drying; "Wash
       in warm water and tumble dry"
    10: suffer a sudden downfall, overthrow, or defeat
    11: do gymnastics, roll and turn skillfully