Call Center: A call center that provides various call answering and call processing services to third parties for a fee. Sometimes called Teleservice Companies or a Service Bureau. This term is sometimes also used to encompass telephone answering services or telemessaging services. See Outsourcer.
when, instead of you doing it you hire someone else to do some work that is part of your business, that is outsourcing. It can be any part of your business: answering email, filing, web design, promotion, product or e-book creation, service maintenance, etc.