gloss is a Sindarin word meaning snow-white or dazzling white.
In the first book of the Lord of the Rings, The Fellowship of the Ring, the four hobbits (Samwise Gamgee, Frodo Baggins, Peregrin Took and Meriadoc Brandybuck), on their way to Buckleberry over the Brandywine, hear the High Elves of the House of Finrod singing a song of Elbereth. They were hid out of sight from the road they travelled, for fear of the Black Riders, and the Elves had began singing just in time to save the Hobbits from an untimely demise.
Frodo's translation of the song is as follows:
Snow-white! Snow-white! O Lady clear!
O Queen beyond the Western Seas!
O Light to us that wander here
Amid the world of woven trees!
Gilthoniel! O Elbereth!
Clear are thy eyes and bright thy breath!
Snow-white! Snow-white! We sing to thee
In a far land by the Sea.
O stars that in the Sunless Year
With shining hand by her were sown,
In windy fields now bright and clear
We see your silver blossom blown!
O Elbereth! Gilthoniel!
We still remember, we who dwell
In this far land beneath the trees,
Thy starlight on the Western Seas.