'adonai' originates from Hebrew, specifically the word 'אֲדֹנָי', where 'adon' meant 'lord' or 'master'.

The term 'adonai' has been used in Jewish liturgy and scripture to refer to God, maintaining its original form and meaning.

Initially, it meant 'lord' or 'master', but over time it evolved into its current usage as a reverent name for God.