Sindarin: Adorn (as also known in English, German)
References: Case-sensitive: LR(2), LR/Index(2), UT(7) Case-insensitive: UT(1), I(4), II(1), III(2), V(1)
Adorn — Tolkien Gateway
Adorn — The Thain's Book
Adorn / River Adorn, Rohans western border. — Encyclopedia Arda