The Collaborative International Dictionary of English v.0.48:

Ditty \Dit"ty\, n.; pl. Ditties. [OE. dite, OF. diti['e], fr.
   L. dictatum, p. p. neut. of dictare to say often, dictate,
   compose. See Dictate, v. t.]
   1. A saying or utterance; especially, one that is short and
      frequently repeated; a theme.
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            O, too high ditty for my simple rhyme. --Spenser.
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   2. A song; a lay; a little poem intended to be sung.
      "Religious, martial, or civil ditties." --Milton.
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            And to the warbling lute soft ditties sing.
                                                  --Sandys.
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