Useful Hide Peacock

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.

Old English hȳd, skin / hide. As a color modifier, hide implies a tanned-leather-and-skin quality, the visual register of cattle-and-deer-and-pig-hide hand-tanned-and-vegetable-tanned cattle-and-deer-and-pig-skin hand-tanned-leather-hide surfaces under tanned-leather-and-skin tanning-yard light. Sits at the modifier-and-texture end of the grid, parallel to pelt and fur in usage.

Pavo cristatus, the Indian peafowl whose male displays the most elaborate sexual ornament in birds — a fan of two-meter eyespotted tail feathers in iridescent blue-green. The color is structural, not pigmented: created by interference patterns in the feather barbules. Peacock blue refers to the dominant body color: a saturated, slightly muted teal-blue with the optical depth of structural color. Cooler than persian, warmer than sapphire.