1. One is permitted to carry within an area enclosed by walls (a private
domain), only if the area was enclosed for dwelling purposes.
What is meant by "enclosed for dwelling purposes ('Hukaf
LeDira')"? Building a house or opening a doorway from one's house, and
then enclosing the area with partitions, in the way one generally creates
courtyards around houses; in such an instance, even if the area is
extremely large, it retains its status as a private domain [and hence, one
may carry within it].
In contrast, areas that are not enclosed for the purpose of dwelling,
like gardens or orchards, which are enclosed only to protect the trees and
plants growing there, are classified according to their size. If the
enclosed area would not require more than two "seahs" [of seed to sow it],
one is permitted to carry within it; however, if the area is large enough
to require more than two "seahs" [of seed], it is given the status of a
"carmelis" [and hence, one would not be allowed to carry within it] (1).
(1) The dimensions of an area requiring two "seahs" of seed will be
discussed in the next halacha.