Shards is more defined like a floating rock piece while would contain one or more linked areas.
In case of the starter area Hawksmouth there is a portal in the city through which you would teleport to the area of Aldenvault.
Both areas are on the same shard, but are different map files on also have split chats.
Going through a teleport "door" and after loading the map and new character postion would normally give you the new zone info and in case of a pvp area a countdown
from 5 secs downto 0 before pvp was enabled.
This also had a know bug, other players could only attack you when you moved position once the pvp countdown was gone, so by just standing there you could see what was happening around you without being hurt.