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Serrhēum (-rhīum, -rīum), i, n., a promontory in Thrace, with a fortification: alia castella, Cypsela et Doriscon et Serrheum, Liv. 31, 16, 5; Mel. 2, 2, 8.
Form Serrium, Plin. 4, 11, 18, § 43.