Hourly staff
Staff who are paid by the hour as opposed to receiving a set salary (see “Salaried employee”) are often referred to as “hourly staff”.
Hourly staff are more common in some industries than others — for example, restaurants, cafes, and bars — owing to the nature of the work they do and the fact that they may often end up working more hours than they’re scheduled due to customer demand.
Although they’re also often paid by the hour, “zero-hours” staff are not strictly the same thing as hourly staff, since many hourly staff are contracted to work a minimum number of hours per week or month.