Certain Tile 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 tigele, roof-tile. As a color modifier, tile implies a fired-clay-or-stone-flat quality, the visual register of Spanish-and-Italian-and-Persian-tile hand-fired-and-glazed clay-and-stone-and-marble Spanish-and-Italian-and-Persian-tile surfaces under Spanish-and-Italian-and-Persian-tile workshop-light. Sits at the modifier-and-texture end of the grid, parallel to slab and plate 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.