Planasĭa, ae, f., = Πλανασία, an island in the Tyrrhenian Sea, south of Ilva (Elba), now Pianosa, Varr. R. R. 3, 6; Plin. 3, 6, 12, § 81; Tac. A. 1, 3; Mart. Cap. 6, § 644.