Most people refer to it as being a "socket = thing that holds the CPU", be it Ball Grid or Pin Grid, so non-technical people or "somewhat-technical" folks can understand what it's being talked about. If we start using hard fancy terms, then more questions arise.
Getting back to topic - Changing a BGA CPU is not worth anybody's time, nor money. OP should better focus on upgrading to a SSD, the improvement will be quite impressive.