double-figure

The compound adjective "double-figure" is a modern English formation that logically combines two established words to create a specific numerical category. "Double" originates from the Latin duplus, meaning "twofold," which itself derives from the Proto-Indo-European root \dwo-, the source for "two." "Figure," in the sense of a written number, comes from Latin figura, meaning "shape" or "form," tracing back to the PIE root \dheigh- (to form, build). The term's logic is transparent: it literally denotes a number requiring two digit-figures to write, evolving from these concrete roots of "twofold" and "form" to its precise modern abstract meaning of any integer from 10 to 99.

Structure: double (twofold) + figure (number) - double: From Latin duplus (twofold, double). In this compound, it functions as a modifier meaning "consisting of two." - figure: From Latin figura (shape, form, figure). In this compound, it functions as the core noun meaning "a numerical digit."