The hill on which Ephel Brandir was built (S/216). The first element is amon “hill”, but the meaning of the second element is unclear. It might be a lenited form ’obel of gobel “walled house or village, town”, but in Tolkien’s later writings, nouns were not usually lenited in this position. A likelier explanation is that the second element might be the Halathian word obel “town”.
Sindarin
Amon Obel
noun. hill-village
amon obel
place name. Amon Obel
Elements
Word Gloss amon “hill, mountain with steep sides; lump, clump, mass, hill, (isolated) mountain; lump, clump, mass; [G.] steep slope” obel “town”
Amon Obel
Fortified Hill
amon (“hill, steep-sided mount”) + obel (“walled house or village”) #The second element is found in Obel Halad (possibly “town of chieftain”) .