"universal sea," such as that which surrounded Pangaea, 1893 (Suess), from Greek pan- "all" (see pan-) + thalassa "sea" (see thalasso-).

before vowels thalass-, word-forming element meaning "sea, the sea," from Greek thalassa "the sea" (in Homer, when used of a particular sea, "the Mediterranean," as opposed to ōkeanos), a word from the Pre-Greek substrate language. In Attic Greek thalatta, hence sometimes thalatto-.