The most common Quenya word for “river”, derived from the root √SIR “flow”.
Conceptual Development: This word first appeared as ᴱQ. sīre “stream” as a derivative of ᴱ√SIŘI [SIÐI] (QL/84), and this form and gloss also appeared in the contemporaneous Poetic and Mythological Words of Eldarissa (PME/84). The form ᴹQ. siri- “river” appeared in the Declension of Nouns (DN) from the early 1930s, along with uninflected sire with short i and various inflected forms with siry- (PE21/10). The form sīre “river” with long ī appeared in The Etymologies of the 1930s as a derivative of ᴹ√SIR “flow” (Ety/SIR; EtyAC/SIR). In several notes from the mid-1960s, it appeared in monosyllabic form sír (PE17/65) or sīr (VT49/17), but it had dual form siryat from the late 1960s implying a stem form of sirĭ- and a development similar to that of DN from the early 1930s (VT47/11).
Neo-Eldarin: Its form síre is probably better known and more commonly used in Neo-Quenya. For example this is the typical form in Helge Fauskanger’s NQNT (NQNT).