1. 
[syn: double, dual, duple]
The Collaborative International Dictionary of English v.0.48:
Duple \Du"ple\, a. [L. duplus. See Double.]
   Double.
   [1913 Webster]
   Duple ratio (Math.), that in which the antecedent term is
      double the consequent, as of 2 to 1, 8 to 4, etc.
      [1913 Webster]
WordNet (r) 3.0 (2006):
duple
    adj 1: consisting of or involving two parts or components
           usually in pairs; "an egg with a double yolk"; "a double
           (binary) star"; "double doors"; "dual controls for pilot
           and copilot"; "duple (or double) time consists of two (or
           a multiple of two) beats to a measure" [syn: double,
           dual, duple]