Sern in UT/463 is a misprint, see VT/42:11
Noldorin
argonath
place name. King Stones
sern aranath
place name. King Stones
gondrafn
noun. hewn stone
gondram
noun. hewn stone
gonn
noun. great stone, rock
sarn
noun. stone (as a material)
sarn
noun. small stone
Sern in UT/463 is a misprint, see VT/42:11
Earlier name for the Argonath appearing in Lord of the Rings drafts from the 1940s (TI/366), a combination of the plural of sarn “stone” and the class-plural of aran “king”. It also appeared with the ordinary plural Sern Erain, and the singular form Sarn Aran (WR/98).