a. Math. [ad. late L. subduplus: see SUB- 10 and DUPLE a.] That is half of a quantity or number; denoting a proportion of one to two; (of a ratio) of which the antecedent is half the consequent.
1609. Dowland, Ornith. Microl., 63. Euery Proportion is … taken away by the comming of his contrary proportion…. As by the comming of a subduple, a dupla is taken away, and so of others.
1648. [see SUB- 10].
1706. W. Jones, Syn. Palmar. Matheseos, 55. The Ratio of 3 to 6 is 3/6 = 1/2 or subduple.
1715. trans. Gregory’s Astron. (1726), II. 841. The number will be about subduple in a Jovial Year.
1728. Chambers, Cycl., s.v. Subnormal, The Subnormal PR is Subduple the Parameter.
1740. Phil. Trans., XLI. 426. Let us take … Two Points at Pleasure, the Point A in the Circumference of the Equator, and the Point C in the Circumference of a subduple parallel Circle.
