Thalassic is a hypothetical language family proposed by Jörg Rhiemeier, being the language family of the Mediterranean Neolithic (the Cardial-Impresso culture). The unit is named after thalassa, the Greek word for 'sea', used especially in reference to the Mediterranean Sea.
It is very uncertain whether such a language family existed, though. There is some genetic evidence in favour of these cultures having been spread by immigration of farmers (demic diffusion), which makes the existence of a Thalassic language family plausible, but genes and languages do not always travel together. It is likely that Basque is the last surviving member of this family. It is also possible, but entirely uncertain, that the languages of the Mediterranean Neolithic farmers were related to the languages of the Neolithic farmers north of the Alps, but the latter are entirely unknown (a relationship to the Indo-European languages appears unlikely).