Lewis & Short

Rhĭon or Rhĭum, i, n.

  1. I. A strait between the Ionian Sea and the Corinthian Gulf, Liv. 27, 29; 28, 7; Mel. 2, 3.
  2. II. A promontory of Achaia near this strait, now Kastro Morea, Plin. 4, 2, 3, § 6.
  3. III. A town near the same strait, Liv. 27, 30 (al. Aegium).