The Collaborative International Dictionary of English v.0.48:

Mandioc \Man"di*oc\, Mandioca \Man`di*o"ca\, n. (Bot.)
   See Manioc.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Manioc \Ma"ni*oc\, n. [Pg. mandioca, fr. Braz.] (Bot.)
   The tropical plants (Manihot utilissima, and Manihot
   Aipi), from which cassava and tapioca are prepared; also,
   cassava. [Written also mandioc, manihoc, manihot.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

mandioc
    n 1: cassava with long tuberous edible roots and soft brittle
         stems; used especially to make cassiri (an intoxicating
         drink) and tapioca [syn: bitter cassava, manioc,
         mandioc, mandioca, tapioca plant, gari, Manihot
         esculenta, Manihot utilissima]