The Collaborative International Dictionary of English v.0.48:

Dwindle \Dwin"dle\, v. i. [imp. & p. p. Dwindled; p. pr. & vb.
   n. Dwindling.] [From OE. dwinen to languish, waste away,
   AS. dw[imac]nan; akin to LG. dwinen, D. dwijnen to vanish,
   Icel. dv[imac]na to cease, dwindle, Sw. tvina; of uncertain
   origin. The suffix -le, preceded by d excrescent after n, is
   added to the root with a diminutive force.]
   To diminish; to become less; to shrink; to waste or consume
   away; to become degenerate; to fall away.
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         Weary sennights nine times nine
         Shall he dwindle, peak and pine.         --Shak.
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         Religious societies, though begun with excellent
         intentions,
         are said to have dwindled into factious clubs. --Swift.
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The Collaborative International Dictionary of English v.0.48:

Dwindle \Dwin"dle\, v. t.
   1. To make less; to bring low.
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            Our drooping days are dwindled down to naught.
                                                  --Thomson.
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   2. To break; to disperse. [R.] --Clarendon.
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The Collaborative International Dictionary of English v.0.48:

Dwindle \Dwin"dle\, n.
   The process of dwindling; dwindlement; decline; degeneracy.
   [R.] --Johnson.
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WordNet (r) 3.0 (2006):

dwindle
    v 1: become smaller or lose substance; "Her savings dwindled
         down" [syn: dwindle, dwindle away, dwindle down]