SUBDUPLE

Etymology

Adjective

subduple (not comparable)

(mathematics) Indicating one part of two; in the ratio of one to two.

As one of these under pulleys abates half of that heaviness of the weight, and causes the power to be in a subduple proportion; so two of them abate half of that which remains, and cause a subquadruple proportion, three a sextuple, four a suboctuple.

Source: Wiktionary

Sub"du*ple, a. (Math.)

Definition: Indicating one part of two; in the ratio of one to two. Subduple ratio, the ratio of 1 to 2: thus, 3:6 is a subduple ratio, as 6:3 is a duple ratio.

Source: Webster’s Unabridged Dictionary 1913 Edition