SJSinNYC:
Regarding what?
In general, a Chatzer is a common area in front of a number of individual homes, which opens to a “Mavuyi”, which goes into the street. Most “Tashmishin” are done in this Chatzer (Rashbam).
This Chatzer may or may not have the right to be private if it is owned by an individual, see Hezek Reiyah (begining of Bava Basra).