A regulated occupation is a profession or skilled trade in a province or territory that is covered under legislation (Acts and regulations) and overseen by a regulatory body. The regulatory body defines what you can and cannot do as part of your work in order to ensure public protection. Doctors, engineers, welders, roofers, industrial mechanics and electricians are all examples of certified workers in regulated occupations.
The regulatory body can also require their members to be certified or registered in order to use a title (for example Medical Doctor, Lawyer, Professional Engineer, Chartered Professional Accountant, Registered Nurse,  etc.).  In some cases, an occupation may be regulated in some provinces and territories but not in others.  For example, psychotherapists are regulated in some provinces but not in others.
Contact your  Labour Mobility Coordinator if you are unsure whether your occupation is regulated in a specific province or territory.