- (linguistics) The last phase of Proto-Slavic language, the Late Proto-Slavic.
The term Proto-Slavic is often used synonymously with the term Common Slavic, denoting a proto-language stage after the loss of quantitive oppositions and monophthongisations, but more proper linguistic use prescribes the usage of the term Proto-Slavic as synonymous with Early Proto-Slavic (c. 600 CE), and Common Slavic as synonymous with Late Proto-Slavic (ca. 8th–9th centuries CE). In its attributive usage, the noun denotes a historical period when Slavic sound changes occurred in all or almost all Slavic dialects (ca. 7th–10th centuries).