The history of legal lexis dates back to the ancient times of ancient peoples. The study of legal language enables the reconstruction of Indo-European ritual-legal ancients at verbal, linguistic levels. Archaic societies had no legal culture, instead, the norms of customary law of ancient societies were referred to as “pre-law”, which included syncretism of law, religion, myth, poetry, and morality. The syncretic ritual and legal consciousness of the ancient peoples in the pre-state period and in the early state formations has its specific reflection in a language that receives such a definition as “the language of law”. The system of “language of law” of Indo-European peoples is partly outlined in today’s scientific survey by describing changes in the semantics of legal lexis in the Indo-European languages, based on the analysis of the distinguished evolutionary models of semantics (EMS) in the Germanic, Slavonic and Iranian languages. The evolutionary model of semantics is a method of inquiry and a procedural scheme for explaining the history of legal meaning. 79 EMS were distinguished during the research, showing the genesis of the meaning 'power', 'lord', 'to rule', 'law', '(religious) law', 'pledge', '(blood) feud', 'court', 'judge'. Using data of the distinguished EMS, that clearly shows the change in the semantic volume of a word, a specific type of change in the meaning of legal lexis in the lexical and semantic system of the Indo-European languages was identified for each EMS, namely, expanding, narrowing (specializing), amelioration or pejoration of the meaning of the word. The study found that quantitatively the semantic derivation of the Indo-European legal terminology most experienced the type of narrowing of the meaning of the word, which, according to the researchers, belongs to the semantic universals. Metaphorical and metonymic changes in the meaning in the legal lexis of the Indo-European languages were also highlighted, that will need further study.