The Serni was a short river of southern Gondor; it rose beneath the eastern White Mountains, and flowed southwestward through Lebennin until it met the River Gilrain at Linhir. Then it opened into a delta, joining the larger Ethir Anduin. That mouth was blocked with shingles, and ships that entered the Ethir Anduin preferred to enter it east of Tol Falas.
The name Serni is an "adjectival formation" deriving from Sindarin sarn ("small stone, pebble"), the equivalent of Quenya sarnie (sarniye) meaning 'shingle, pebble bank'. The meaning is therefore "stony".
The name of the river is spelled Serni in the maps of The Lord of the Rings. In the footnote 1 of the Preface of The Adventures of Tom Bombadil it was spelled Sernui until the 2014 edition, where the editors Christina Scull and Wayne G. Hammond have changed the name to Serni, considering Sernui "very likely a typographic error for Serni" even though they refer to a comment by Carl F. Hostetter who informed them that sernui "would be possible as an unattested adjectival formation *'stony' from sarn 'stone'".
 Portrayal in adaptations
2014: The Lord of the Rings Online:
- The river Serni was found in Lower Lebennin in the region of Central Gondor. As its name indicated,[source?] it was strewn with rocks. There were two fords, with the western one being south of the town of "Malbarth" and the eastern one south of "Ost Anglebed". The Serni was the domain of the stern River-maid Grey-eye, one of the Five Sisters, though she and her sisters were widely considered a myth by the time of the War of the Ring.
- ↑ J.R.R. Tolkien, The Lord of the Rings, The Return of the King, "Map of Rohan, Gondor, and Mordor"
- ↑ 2.0 2.1 J.R.R. Tolkien, "The Rivers and Beacon-hills of Gondor" (edited by Carl F. Hostetter), in Vinyar Tengwar, Number 42, July 2001, p. 11
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, Index
- ↑ Robert Foster, The Complete Guide to Middle-earth, p.348
- ↑ J.R.R. Tolkien, The Adventures of Tom Bombadil, "Preface"
- ↑ J.R.R. Tolkien, The Lord of the Rings, Appendix B, Expanded edition 2014, edited by Christina Scull and Wayne G. Hammond, Commentary, p. 120-121; cf. Preface, p. 31.