Places in Middle-earth
Region: Beleriand & North
Meaning: Tower of the Well
Other Names fortress of Eithel Sirion
Fingolfin and Fingon's] chief fortress was at Eithel Sirion in the east of Ered Wethrin, whence they kept watch upon Ard-galen; and their cavalry rode upon that plain even to the shadow of Thangorodrim....
The Silmarillion, Quenta Silmarillion, Ch 14, Of Beleriand and its Realms
But the Captain of Morgoth... marched on therefore until the front of his battle was drawn up before the stream of Sirion, from the walls of the fortress of Eithel Sirion to the inflowing of Rivil at the Fen of Serech; and the outposts of Fingon could see the eyes of their enemies.... Then the Captain of Morgoth sent out riders with tokens of parley, and they rode up before the outworks of the Barad Eithel.
The Silmarillion, Quenta Silmarillion, Ch 20, Of The Fifth Battle: Nirnaeth Arnoediad
barad 'tower' in Barad-dûr, Barad Eithel, Barad Nimras; the plural in Emyn Beraid.
The Silmarillion, Appendix: Elements in Quenya and Sindarin Names
kel- 'go away', of water 'flow away, flow down', in Celon; from et-kele 'issue of water, spring' was derived, with transposition of the consonants, Quenya ehtele, Sindarin eithel.
Elena Tiriel 10Dec07, 14Mar11