Flow restrictors, flow regulators, and flow limiters are used interchangeably. They are all ways to describe the exact same result that they deliver: restriction, regulation, and limitation of a flow. Sometimes the word “valve” is also added on to these first three terms as well. For example, flow restrictor valve. The word “valve” is a general term used very broadly for something that slows or shuts off flow. The tap to a garden hose is a “valve”.
Balancing valves are sometimes also used as an interchangeable term for flow restrictors, but that is incorrect as their usual meaning is a bit different from the others. Balancing valves are used in HVAC applications to maintain certain flow conditions within a heating or colling system to assure that the heating or cooling function is operating the same system wide. If a system is “balanced”, it is operating correctly. If a system is “unbalanced”, then it results in situations like some tenants of an apartment building being delivered too much heat and some tenants not receiving hardly any heat. Balancing valves also control flow, but the nuance of what they do is a little different than flow restrictors.