(linguistics, uncountable) The hypothetical ancestor language or protolanguage of most Polynesian languages.

(anthropology, countable) A person who spoke the Proto-Polynesian language.

(linguistics, anthropology) Of or pertaining to the Proto-Polynesian language, or the people who spoke it.

(linguistics) A hypothetical, reconstructed language whence all the Slavic languages later descended.

Of or pertaining to the Proto-Slavic language / Of or pertaining to the people or nation that spoke Proto-Slavic

The putative ancestor of all the known Celtic languages.

A proposed common ancestor of the group of Oceanic languages.

The hypothetical protolanguage of Semitic languages.

plural of proto-language

(genetics) A gene, that promotes the specialization and division of normal cells, that becomes an oncogene following mutation.