1787, from Scottish, apparently an alteration of M.E. glenten
"gleam, flash, glisten," from Scand. (cf. Norw. gletta
"to look," dial. Swed. glinta
"to shine"), from P.Gmc. *glent-,
from PIE *ghlei-
"to shine, glitter, glow, be warm" (see gleam
). Introduced into Eng. by Burns.