'actus servi in iis quibus opera ejus comminiter adhibita est actus domini habetur' means:
'the act of a servant, in those things in which he is usually employed, is considered the act of his master'.
This is a ‘legal maxim’ that expresses the principle of ‘Vicarious Liability’; which holds that, a master is responsible for the actions of his servant, and or agent, within the scope of his employment¹².
This maxim can be traced back to the Roman law, where it was applied to cases of delicts (or torts) at common law, committed by slaves or freedmen³.