1.NounA bioluminescent phenomenon observable on some moonless nights, caused by luminous plankton and bacteria, which make the seawater glow a milky whitish or pale bluegreen colour; seafire, especially when it occurs in the Indian Ocean.
"A milky sea shines from horizon to horizon like a field of fresh snow (when only the surface layers shine) or a cloud (when deeper layers also shine). This phenomenon occurs most often in the Indian Ocean and off Indonesia."