What is the origin of thalassic?
Thalassic “pertaining to seas or oceans, growing or found in the sea” is a relatively rare technical term used in oceanography, usually applied to bodies of salt water such as gulfs or bays that are smaller than oceans. The adjective comes ultimately from the Greek noun thálassa, thálatta “sea, the sea, the Mediterranean Sea.” Thálassa has no reliable etymology but is from the same pre-Greek language that gave Greek an alternative form to thálassa, thálatta, namely, dalánkha, recorded only once, in a dictionary of the 5th century a.d.
Early in “Telemachus,” the first chapter of Ulysses, the irrepressible Malachi “Buck” Mulligan tries to convert a sullen Stephen Dedalus from Catholicism to Hellenism: “Ah, Dedalus, the Greeks…. You must read them in the original. Thalatta! Thalatta!” But Buck’s Hellenism is as shallow as everything else about him: he would have seen thalatta thalatta in his second or third semester of high school Greek in Book 4, Chapter 7 of the Anabasis of Xenophon, whose works were much read as school texts because of the simplicity of his style. The word thalassic entered English in the mid-18th century.