The heart of Mount Doom, translated “Chambers of Fire” (LotR/942), a combination of the class-plural of sam “chamber” and the noun naur “fire”.
Sindarin
Sammath Naur
place name. Sammath Naur
sammath naur
place name. Chambers of Fire
Sammath Naur
noun. chambers of fire
sam(b) (“chamber, room”) + ath (collective plural suffix), naur (“fire”)
topon. >> naur