If you supervise a place where work is done, you ensure that the work there is done properly. He makes the wines and supervises the vineyards. to be in charge of an activity or person, and make sure that things are done in the correct way (past participle of supervidere, from videre )
If you supervise an activity or a person, you make sure that the activity is done correctly or that the person is doing a task or behaving correctly. University teachers have refused to supervise students' examinations