od (from odog, Q otso “seven”) + sîr (“river”) + and (commonly used suffix in the names of regions and countries)
Sindarin
ossiriand
place name. Land of Seven Rivers
Ossiriand
noun. land of seven rivers
Ossiriand
place name. 'Land of Seven Rivers'
topon. 'Land of Seven Rivers'.
dúnedhel
beleriand, elf of
(i Núnedhel), pl. *Dúnedhil*** (i Ndúnedhil*) (WJ:378, 386)*
A region in eastern Beleriand translated Ossiriand glossed “Land of Seven Rivers” (S/94), a reduction of primitive otoso “seven” combined with sîr “river” and the suffix -ian(d) “-land” (RC/384).
Conceptual Development: In the earliest Silmarillion drafts from the 1930s, this name first appeared as Assariad (SM/133) and on early maps as Ossiriath “of the Seven Rivers” (SM/233), but was soon revised to N. Ossiriand “Land of Seven Streams” (SM/116), the form it retained thereafter. Later in the 1930s its gloss was changed to “Land of Seven Rivers” (LR/128).