The ongoing effort to raise the effectiveness of a management system over time, a core requirement of every ISO standard.
Continual improvement is the requirement that a management system gets better over time rather than standing still. It draws on audit findings, incidents, performance metrics, and management reviews to identify where the system can be strengthened.
In practice it shows up as a steady flow of corrective actions and improvements, each tracked from identification to verification, so an auditor can see the system learning from its own results.