In my book it says that:
The access network is the network that physically connects an end system to the first router (edge router).
While also:
A local area network (LAN) is used to connect an end system to the edge router.
Which sounds very much the same, so what's the difference between them?
I have done googleing, and by looking at some of the picture, it seems almost like LAN is the Ethernet that is the first step for the end systems to go through before they reach the first router. But are both the Ethernet and the first router considered to be the ISP access? Or is it just the first router and not the Ethernet that is considered to be the ISP access?
ISP implies internet service; LAN implies local area. So, you might have a company with three offices. All of which might be connected to a "metro" area network, with only one office providing internet connectivity (say to at&t).
Basically, if your network is publicly routable then it is connected to the internet. But not every network is publicly routable (or even connected to the internet), see also NIPRNet.