Elbereth comes from J.R.R. Tolkien's writings set in Middle-Earth, particularly The Lord of the Rings and The Silmarillion; it was the Elves' name for a goddess they particularly revered. A song in her praise proves to have bad effects on Sauron's minions in The Lord of the Rings.
Gilthoniel! O Elbereth!
silivren penna miriel
o menel aglar elenath!
o galadhremmin ennorath,
Fanuilos, le linnathon
nef aear, si nef aearon!
O Elbereth Star-kindler
(white) glittering slants down sparkling like jewels
from [the] firmament [the] glory [of] the star-host!
To-remote distance far-having gazed
from [the] tree-tangled middle-lands,
Fanuilos, to thee I will chant
on this side of ocean, here on this side of the Great Ocean!