Sure Ache Lagoon

Old French seur, certain — used as a color modifier since the medieval period for hues that read as confident and stable. Sure red, sure blue: moderate saturation combined with optical commitment. Sits at the crisp-bucket center alongside steady and true.

Old English acan, to-hurt-or-throb. As a color modifier, ache implies a dull-and-lingering-and-throbbing quality, the visual register of Romantic-poet-and-pining-lover-ache hand-dull-and-lingering-and-throbbing Romantic-poet-and-pining-lover-and-bedside-vigil ached-and-dull-and-lingering-and-throbbing surfaces under Romantic-poet-and-pining-lover-and-bedside-vigil long-night-and-melancholy-and-pining candle-and-rain-window-light. Sits at the modifier-and-mood end of the grid, parallel to pang and throb in usage.

A shallow body of saltwater partially or fully enclosed by a barrier — coral atoll lagoons in the Pacific, Venice's Laguna Veneta, the Florida Keys' backcountry. The color refers to the average reflectance of a calm tropical lagoon at midday: a saturated, slightly muted blue-green with the optical clarity of shallow water over white sand. Brighter than reef, cooler than aquamarine, with the postcard weight of a Pacific atoll seen from above.