The Collaborative International Dictionary of English v.0.48:

Launch \Launch\, v. i.
   To move with force and swiftness like a sliding from the
   stocks into the water; to plunge; to make a beginning; as, to
   launch into the current of a stream; to launch into an
   argument or discussion; to launch into lavish expenditures;
   -- often with out.
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         Launch out into the deep, and let down your nets for a
         draught.                                 --Luke v. 4.
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         He [Spenser] launches out into very flowery paths.
                                                  --Prior.
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The Collaborative International Dictionary of English v.0.48:

Launch \Launch\ (l[add]nch or l[aum]nch), v. i. [imp. & p. p.
   Launched (l[add]ncht or l[aum]ncht); p. pr. & vb. n.
   Launching.] [OE. launchen to throw as a lance, OF.
   lanchier, another form of lancier, F. lancer, fr. lance
   lance. See Lance.] [Written also lanch.]
   1. To throw, as a lance or dart; to hurl; to let fly.
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   2. To strike with, or as with, a lance; to pierce. [Obs.]
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            Launch your hearts with lamentable wounds.
                                                  --Spenser.
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   3. To cause to move or slide from the land into the water; to
      set afloat; as, to launch a ship.
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            With stays and cordage last he rigged the ship,
            And rolled on levers, launched her in the deep.
                                                  --Pope.
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   4. To send out; to start (one) on a career; to set going; to
      give a start to (something); to put in operation; as, to
      launch a son in the world; to launch a business project or
      enterprise.
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            All art is used to sink episcopacy, and launch
            presbytery in England.                --Eikon
                                                  Basilike.
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The Collaborative International Dictionary of English v.0.48:

Launch \Launch\, n.
   1. The act of launching.
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   2. The movement of a vessel from land into the water;
      especially, the sliding on ways from the stocks on which
      it is built.
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   3. [Cf. Sp. lancha.] (Naut.) The boat of the largest size
      belonging to a ship of war; also, an open boat of any size
      driven by steam, naphtha, electricity, or the like.
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   Launching ways. (Naut.) See Way, n. (Naut.).
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WordNet (r) 3.0 (2006):

launch
    n 1: a motorboat with an open deck or a half deck
    2: the act of propelling with force [syn: launching, launch]
    v 1: set up or found; "She set up a literacy program" [syn:
         establish, set up, found, launch] [ant: abolish,
         get rid of]
    2: propel with force; "launch the space shuttle"; "Launch a
       ship"
    3: launch for the first time; launch on a maiden voyage; "launch
       a ship"
    4: begin with vigor; "He launched into a long diatribe"; "She
       plunged into a dangerous adventure" [syn: plunge, launch]
    5: get going; give impetus to; "launch a career"; "Her actions
       set in motion a complicated judicial process" [syn: launch,
       set in motion]
    6: smoothen the surface of; "launch plaster"