The chief river of Númenor (UT/168). This name probably contains sír(ë) “river”, but the exact meaning of the name is unclear. It is identical in form to earlier ᴹQ. siril “rivulet” (Ety/SIR), but given the size of the river, it seems unlikely this is the later meaning.
place name. Siril
Word Gloss sír(ë) “river, river, [ᴱQ.] stream” ?
siril noun "rivulet" (SIR)