Source : Webster's Revised Unabridged Dictionary (1913)

Kinglet \King"let\, n.
   1. A little king; a weak or insignificant king. --Carlyle.

   2. (Zo["o]l.) Any one of several species of small singing
      birds of the genus {Regulus} and family {Sylviid[ae]}.

   Note: The golden-crowned kinglet ({Regulus satrapa}), and the
         rubycrowned kinglet ({R. calendula}), are the most
         common American species. The common English kinglet
         ({R. cristatus}) is also called {golden-crested wren},
         {moonie}, and {marigold finch}. The kinglets are often
         popularly called {wrens}, both in America and England.

Source : WordNet®

kinglet
     n : small birds resembling warblers but having some of the
         habits of titmice