Blue

The color name "Blue" has been approved in accordance with the internal procedures of The Official Register of Color Names.

Record Validation Evidence: Wikipedia/Blue

The modern English word blue comes from Middle English bleu or blewe, from the Old French bleu, a word of Germanic origin, related to the Old High German word blao (meaning 'shimmering, lustrous'). In heraldry, the word azure is used for blue.

In Spanish and some other languages, there is no single word for blue, but rather different words for light blue (Celeste) and dark blue (Azul).

Several languages, including Japanese and Lakota Sioux, use the same word to describe blue and green. For example, in Vietnamese, the colour of both tree leaves and the sky is xanh. In Japanese, the word for blue is often used for colours that English speakers would refer to as green, such as the colour of a traffic signal meaning "go". In Lakota, the word tȟó is used for both blue and green, the two colours not being distinguished in older Lakota. (For more on this subject, see Blue–green distinction in language.)

The digital color #0000FF, known as "Blue", is classified in the Register under the Blue Color Family, with Full Saturation and Light brightness. Its exact recipe is rgb(0, 0, 255) — 0% red, 0% green, 100% blue — and for print it converts to CMYK 100 / 100 / 0 / 0. New to color codes? See our guide to RGB color codes.

#0000FF presents itself as a maximally vivid blue — one that sits on the lighter side of the spectrum. In practice it works well for bold branding moments and attention-grabbing details. In The Official Register of Color Names it is very close to Primary Blue (#0804F9). Nearby in the Register you will also find Strong Blue (#0C06F7) and Samanthas blue (#0F0FFF).

In RGB terms — rgb(0, 0, 255) — the blue channel does the heavy lifting here. If you plan to put text on a #0000FF background, choose white — the contrast ratio is 8.6:1 (passing WCAG AAA), while black manages only 2.4:1. This precise shade carries the officially registered name "Blue" in the Register.