An Etymological Dictionary of Astronomy and Astrophysics

1. General: A bright → burst of fire, a flame; a bright or steady light or glare.
   

2. Optics: The concentration of a limited region of the spectrum into any → order other than the zero order.

Etymology (EN): O.E. blæse “a torch, flame,” from P.Gmc. *blason, from PIE *bhel- “to shine.”

Etymology (PE): Beliz, from Lori beleyz “flame, blaze,” Kordi belise “flame, blaze,” Mid.Pers. brâh, Av. braz- “to shine, gleam, flash, radiate,”
cf. Skt. bhâ- “to shine,” bhrajate “shines, glitters,” O.H.G. beraht “bright,” O.E. beorht “bright;” PIE *bhereg- “to shine.”