A white mark in the forehead of a horse. (Icelandic, blesi, a white star on the forehead of a horse; German, blasz, pale.)
A star is a sort of white diamond in the forehead. A blaze is an elongated star or dash of white.
“Guided by the blazed trees ... they came to the spot.” —Goulding: The Young Marooners, 118.
“They buried him where he lay, a blazed tree marking his last resting-place.” —Adventures in Mashonaland, p. 158.
(To). To blaze abroad. To noise abroad is the German verb blasen, to blow or sound. Shakespeare uses the noun blazon:
But this eternal blazon must not be To ears of flesh and blood.
Hamlet, i. 5.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894