An element in the Entish phrase Taurelilómëa-tumbalemorna Tumbaletaurëa Lómëanor (LotR/467), which in one place Tolkien described as meaning “very dark, full of darkness”, a combination of the prefix li(n)- “many” and lómëa “shadowed, gloomy”. A more literal interpretation would be “having many nights”; compare lilótëa “having many flowers” (VT42/18). As such, I think it is safe to say this word is a poetic Entish elaboration, not likely to be used in ordinary Quenya speech.