MAP

Orthanc

Sindarin: Orthanc ‘Mount Fang’ (as also known in English, German)

orod S – mountain E
thanc S – fang E
orod + thanc → orthanc S

References: Case-sensitive: LR(83), LR/Index(6), FR(7), TT(54), RK(16), S(3), UT(30), VI(1), VII(24), VIII(91), IX(22), XII(12) Case-insensitive: LR(2), FR(1), TT(1), VII(1), VIII(2)

Orthanc — Tolkien Gateway

Isengard & Orthanc — The Thain's Book

Mount Fang, A name for the tower of Orthanc. — Encyclopedia Arda

Orthanc, The unbreachable tower within the Ring of Isengard. — Encyclopedia Arda

Tower of Orthanc, Stronghold of Saruman. — Encyclopedia Arda