What is the X in X-mas?
"bright flame, fire," Old English blæse "a torch, flame, firebrand, lamp," from Proto-Germanic *blas- "shining, white" (cf. Old Saxon blas "white, whitish," Middle High German blas "bald," originally "white, shining," Old High German blas-ros "horse with a white spot," Middle Dutch and Dutch bles, German Blesse "white spot," blass "pale, whitish"), from PIE root *bhel- (1) "to shine, flash, burn" (see bleach (v.)).
"light-colored mark or spot," 1630s, northern English dialect, probably from Old Norse blesi "white spot on a horse's face" (from the same root as blaze (n.1)). A Low German cognate of the Norse word also has been suggested as the source. Applied 1660s in American English to marks cut on tree trunks to indicate a track; thus the verb meaning "to mark a trail;" first recorded 1750, American English. Related: Blazed; blazing.
"to burn brightly or vigorously," c.1200, from blaze (n.1). Related: Blazed; blazing.
"make public" (often in a bad sense, boastfully), late 14c., perhaps from Middle Dutch blasen "to blow" (on a trumpet), from Proto-Germanic *blaes-an (cf. German blasen, Gothic -blesan), from PIE *bhle-, variant of root *bhel- (2) "to blow, inflate, swell" (see bole).
"to mark" (a tree, a trail), 1750, American English; see blaze (n.2).
To shoot at, either literally or figuratively: The cops blazed away at the villains/ The candidates blazed away on television and radio (1770s+)