The Collaborative International Dictionary of English v.0.48:

Cuddle \Cud"dle\ (k[u^]d"d'l), v. i. [imp. & p. p. Cuddled
   (-d'ld); p. pr. & vb. n. Cuddling (-dl[i^]ng).] [Prob. for
   couthle, fr. couth known; cf. OE. ku[thorn][thorn]en to
   cuddle, or cu[eth]lechen to make friends with. SeeCouth,
   Uncouth, Can.]
   To lie close or snug; to crouch; to nestle.
   [1913 Webster]

         She cuddles low beneath the brake;
         Nor would she stay, nor dares she fly.   --Prior.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

cuddling \cuddling\ n.
   1. holding close in a tender and afectionate manner.
      [PJC]

   2. lying closely together while caressing; nestling together.
      [PJC]

   3. foreplay without contact with the genital organs. [slang]

   Syn: caressing, fondling, hugging, kissing, necking, petting,
        smooching, snuggling.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

cuddling
    n 1: affectionate play (or foreplay without contact with the
         genital organs) [syn: caressing, cuddling, fondling,
         hugging, kissing, necking, petting, smooching,
         snuggling]