No. Modeling agencies only deal with models and have no connections or interest in booking acting work for their models. Acting agencies are sometimes known as "talent" agencies, which means that...
Yes, the different terms can be interchangeable. In general, their job is to match the labor needs of their corporate clients with individuals who have the skill sets necessary to meet those needs.
I've mostly heard that term used in regard to insurance companies. In that instance, it means the agency handles policies from more than one company. They aren't just selling State Farm insurance,...