Access Point Name (APN) is a computer protocol that typically allows a user's computer to access the internet using the mobile phone network.
On a technical level it is a configurable network identifier used by a mobile device when connecting to a GSM carrier. The carrier will then examine this identifier to determine what type of network connection should be created, for example: what IP addresses should be assigned to the wireless device, what security methods should be used, and/or how should it be connected to some private customer network
More here: http://en.wikipedia.org/wiki/Access_Point_Name
On a technical level it is a configurable network identifier used by a mobile device when connecting to a GSM carrier. The carrier will then examine this identifier to determine what type of network connection should be created, for example: what IP addresses should be assigned to the wireless device, what security methods should be used, and/or how should it be connected to some private customer network
More here: http://en.wikipedia.org/wiki/Access_Point_Name