The Collaborative International Dictionary of English v.0.48:

Yelp \Yelp\, v. i. [imp. & p. p. Yelped; p. pr. & vb. n.
   Yelping.] [OE. yelpen, [yogh]elpen, to boast, boast
   noisily, AS. gielpan, gilpan, gylpan; akin to OHG. gelph
   arrogant: cf. Icel. gj[=a]lpa to yelp. Cf. Yap.]
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   1. To boast. [Obs.]
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            I keep [care] not of armes for to yelpe. --Chaucer.
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   2. To utter a sharp, quick cry, as a hound; to bark shrilly
      with eagerness, pain, or fear; to yaup.
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            A little herd of England's timorous deer,
            Mazed with a yelping kennel of French curs? --Shak.
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            At the least flourish of a broomstick or ladle, he
            would fly to the door with a yelping precipitation.
                                                  --W. Irving.
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The Collaborative International Dictionary of English v.0.48:

Yelp \Yelp\, n.
   A sharp, quick cry; a bark. --Chaucer.
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WordNet (r) 3.0 (2006):

yelp
    n 1: a sharp high-pitched cry (especially by a dog) [syn: yip,
         yelp, yelping]
    v 1: bark in a high-pitched tone; "the puppies yelped" [syn:
         yelp, yip, yap]