is a block, or "lot", of land
in a sim
with a minimum size of 4x4m
, not necessarily contiguous (connected), and can be split and joined with other parcels
of the same owner
(but may not cross a into another sim).
A2: If you own the land, you can find out who has objects on it by right-clicking anywhere on your land, clicking on the object's tab, and hitting the refresh button near the bottom.