Kumquat

from WordNet (r) 3.0 (2006)

kumquat
    n 1: any of several trees or shrubs of the genus Fortunella
         bearing small orange-colored edible fruits with thick
         sweet-flavored skin and sour pulp [syn: {kumquat},
         {cumquat}, {kumquat tree}]
    2: small oval citrus fruit with thin sweet rind and very acid
       pulp

from The Collaborative International Dictionary of English v.0.48

kumquat \kum"quat\, n. [Chin. kin keu.] (Bot.)
   any of several trees or shrubs of the genus {Fortunella}
   (formerly {Citrus}) of the rue family ({Rutaceae})
   (especially {Citrus Japonica}) growing in China and Japan
   bearing small orange-colored edible fruits with thick
   sweet-flavored skin and sour pulp; also, any of the small
   acid, orange-colored citrus fruits of such plants, used
   mostly for preserves. [Also spelled {cumquat}.]
   [1913 Webster + WordNet 1.5]