The Collaborative International Dictionary of English v.0.48:

lemanderin \lemanderin\ n.
   A fruit tree (Citrus limonia) which is a hybrid between the
   mandarin orange and the lemon, having a very acid fruit with
   an orange peel; also, the fruit of this tree, the rangpur.

   Syn: rangpur, rangpur lime, Citrus limonia.
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

lemanderin
    n 1: hybrid between mandarin orange and lemon having very acid
         fruit with orange peel [syn: rangpur, rangpur lime,
         lemanderin, Citrus limonia]