Certain Fall Forest

Latin certus, fixed / sure — sharing root with English concern and certify. As a color modifier, certain implies a saturated-and-unambiguous quality where the hue declares its character without hesitation. Sits at the bold-and-confident end of the grid, parallel to assured and decisive in usage.

Old English feallan, to fall / autumn. As a color modifier, fall implies an autumn-leaf-and-harvest quality, the visual register of New-England-and-English-autumn deciduous-leaf-fall maple-and-oak-and-beech autumnal-orange-and-crimson surfaces under Northern-Hemisphere autumn raking light. Sits at the modifier-and-time end of the grid, parallel to yule and reap in usage.

The dense canopy of a temperate or tropical woodland — oak, beech, pine, eucalyptus, mahogany — wherever leaves close above to filter the light below. Forest green refers to the average reflectance of a healthy mid-summer canopy seen from below: a saturated, slightly muted green with the matte finish of layered chlorophyll. Deeper than fern, cooler than olive, with the ecological weight of a word that has named every wooded biome on Earth.