Useful Magnus Teal

Latin ūsus, use — adjectival suffix -ful. As a color modifier, useful implies a clear-and-purpose-serving quality where the hue carries the visual register of helpful-and-supporting design-element. Sits at the crisp-and-functional end of the grid, parallel to practical and serviceable in usage.

Latin magnus, great-or-large. As a color modifier, magnus implies a Latin-great-and-Albertus-Magnus-and-Magna-Carta quality, the visual register of Albertus-Magnus-and-Magna-Carta-magnus hand-Latin-great-and-Albertus-Magnus-and-Magna-Carta Albertus-Magnus-and-Magna-Carta-and-Charlemagne-Carolus-Magnus magnus-and-Latin-great surfaces under Albertus-Magnus-and-Magna-Carta-and-Charlemagne-Carolus-Magnus Cologne-cathedral-and-Runnymede-meadow medieval-Latin-light. Sits at the modifier-and-Latin end of the grid, parallel to opus and virtus in usage.

Anas crecca, the small dabbling duck whose male in breeding plumage sports a chestnut head crossed by a glossy green-blue stripe. The color refers to that stripe — the iridescent panel just behind the eye: a saturated, slightly muted blue-green with the optical depth of structural color rather than pigment. Cooler than cypress, warmer than cerulean, with the ornithological specificity of a color named for one feather of one bird.