[1] : The Collaborative International Dictionary of English v.0.48

uncle \un"cle\, n. oe. uncle, of. oncle, uncle, f. oncle, fr.
   l. avunculus a maternal uncle, dim. of avus a grandfather;
   akin to lith. avynas uncle, goth. aw? grandmother, icel.
   =ai great grandfather.
   1. the brother of one's father or mother; also applied to an
      aunt's husband; -- the correlative of aunt in sex, and of
      nephew and niece in relationship.
      1913 webster

   2. a pawnbroker. slang --thackeray.
      1913 webster

   3. an eldery man; -- used chiefly as a kindly or familiar
      appellation, esp. southern u. s. for a worthy old negro;
      as, "uncle remus." colloq.

            plain old uncle as he socrates was, with his great
            ears, -- an immense talker.           --emerson.
      webster 1913 suppl.

   my uncle, a pawnbroker. slang

   uncle sam, a humorous appellation given to the united
      states government. see uncle sam, in dictionary of noted
      names in fiction.
      1913 webster
see also:
my uncle uncle sam 

[2] : WordNet (r) 2.0

uncle
     n 1: the brother of your father or mother; the husband of your
          aunt ant: aunt
     2: a source of help and advice and encouragement; "he played
        uncle to lonely students"
see also:
aunt 

[3] : Moby Thesaurus II by Grady Ward, 1.0

43 moby thesaurus words for "uncle":
   aunt, auntie, blood brother, brethren, brother, bub, bubba, bud,
   buddy, country cousin, cousin, cousin once removed,
   cousin twice removed, daughter, father, first cousin,
   foster brother, frater, grandnephew, grandniece, granduncle,
   great-aunt, great-uncle, half brother, kid brother, mother, nephew,
   niece, nuncle, nunks, nunky, second cousin, sis, sissy, sister,
   sister-german, sistern, son, stepbrother, stepsister, unc, uncs,
   uterine brother

[4] : Virtual Entity of Relevant Acronyms (Version 1.9, June 2002)

uncle
     unix net for computer security in law enforcement org., usa, unix,
     "u.n.c.l.e."
     
     

Uncle >> U Words
Uncle, definition of term: Uncle
uncle_pag1.html

Uncle Tom >> U Words
Uncle Tom, definition of term: Uncle Tom
uncle+tom_pag1.html

Uncle Sam >> U Words
Uncle Sam, definition of term: Uncle Sam
uncle+sam_pag1.html

Dutch Uncle >> D Words
Dutch Uncle, definition of term: Dutch Uncle
dutch+uncle_pag1.html