What is "bleu celeste"

n. (context heraldry English) A rarely-occurring sky blue tincture, lighter than azure.

Bleu celeste (, "sky blue") is a rarely occurring and non-standard tincture in heraldry (not being one of the seven main colours or metals or the three staynard colours). This tincture is sometimes also called ciel or simply celeste. It is depicted in a lighter shade than the range of shades of the more traditional tincture azure, which is the standard blue used in heraldry.

Generally considered to be European rather than English or Scottish, after the First World War it started to appear in England in arms and badges relating to the Royal Air Force, though it is still doubtful if any more than a dozen examples could be found in British heraldry, and most British heralds consider it unheraldic. While in the post-WWI period bleu-celeste is depicted as a darker shade, in prior times it was depicted as very light, and has even been treated as a metal, as azure charges have been placed on a bleu celeste field, and vice versa.

Regardless, Bleu Celeste is still used by Heraldic authorities, such as the College of arms London, with one example of the Arms of Jacob Flamberg being granted in 2016 using Bleu Celeste in the blazon for the field, mantling and charge, in each case per pale / party with Sable.

"Per pale Bleu Celeste and Sable on a Fess wavy between three Plum Trees eradicated Argent a Wolf courant per pale Sable and Bleu Celeste langued and armed Gules" and "Party Bleu Celeste and Sable doubled Argent"

Bleu celeste can also be seen in the arms of Israel and Peru and also in the arms of former Canadian Governor General Ray Hnatyshyn. In the arms of the University of Natal Athletic Union the azure is defined as "sky blue".