Bright Ache Lime

Old English beorht, shining, luminous — cognate with the German Bracht, splendor. Applied to color since at least the medieval period for hues that read as luminous: not just light in value but optically active, as if scattering more light back than a dimmer color of the same lightness would. Sits at the bright-bucket center alongside vivid and brilliant.

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.

Citrus aurantiifolia and its key-lime cousin — small, intensely sour green citrus carried by Arab traders from Southeast Asia to the Mediterranean by the eleventh century, then to the Caribbean with Columbus. The color refers to the skin of a fully ripe Persian lime: a saturated, slightly yellow-shifted green with the matte finish of citrus rind. Cooler than chartreuse, sharper than sage, with the same chlorophyll the fruit loses if left to ripen to yellow.