Useful Virtus 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 virtus, manliness-and-courage-and-virtue. As a color modifier, virtus implies a Roman-virtus-and-stoic-and-Cardinal-Virtues quality, the visual register of Roman-virtus-and-Stoic-Cardinal-Virtues hand-Roman-virtus-and-stoic-and-Cardinal-Virtues Roman-virtus-and-Stoic-Cardinal-Virtues-and-Marcus-Aurelius virtus-and-Roman-virtus surfaces under Roman-virtus-and-Stoic-Cardinal-Virtues-and-Marcus-Aurelius Republican-Rome-and-Marcus-Aurelius Stoic-virtue-light. Sits at the modifier-and-Latin end of the grid, parallel to senex and dux 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.