violet

Latin viola — the violet flower — named both the plant and its color. Viola comes from a Proto-Indo-European root possibly related to the Greek ion (violet). Roman poets — Virgil, Ovid — used viola as both flower and color adjective. The violet was among the most culturally significant flowers of the ancient Mediterranean: garlands at banquets, perfume for festivals, and the color of the highest rank of purple.

The color violet was never simply the color of violets — the flowers range from pale lavender to deep purple-blue, and the Greco-Roman violet (viola odorata) is typically a rich blue-purple. What matters is the association: violet was the color that flowers were, and flowers were the color that violet meant. The circular naming defined the color by its most beautiful embodiment.

Isaac Newton, in his Opticks (1704), divided the visible spectrum into seven colors — partly influenced by mysticism's love of the number seven. He named violet at the short-wavelength end. The naming of a physics phenomenon after a flower is quietly absurd: electromagnetic radiation at 380-450 nanometers carries the name of Viola odorata. The frequency has nothing to do with gardens.

Violet is distinguished from purple in physics: violet is a spectral color (a single wavelength of light) while purple is a non-spectral color (produced by mixing red and blue). Purple does not appear in a rainbow; violet does. The flower's name, applied to Newton's spectrum, now has a precise technical meaning — a wavelength — that the Romans would have found incomprehensible.