Useful Leo 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 leo, lion-of-the-zodiac. As a color modifier, leo implies a lion-and-fire-sign-and-Sun-ruled-fixed-fire quality, the visual register of Hellenic-Leo-and-Nemean-lion hand-lion-and-fire-sign-and-Sun-ruled-fixed-fire Hellenic-Leo-and-Nemean-lion-and-Hercules-twelve-labors leo-and-lion-and-fire-sign surfaces under Hellenic-Leo-and-Nemean-lion-and-Hercules-twelve-labors high-summer-and-July-and-August fixed-fire-sign-light. Sits at the modifier-and-zodiac end of the grid, parallel to cancer and virgo 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.