Wiktionary
n. A group of news organizations pooling their resources in the collection of news. A video pool or pool feed is then distributed to members of the pool, who are free to edit it or use it as they see fit.
Wikipedia
Press pool refers to a group of news gathering organizations that combine their resources in the collection of news. A pool feed is then distributed to members of the broadcast pool who are free to edit it or use it as they see necessary. In the case of print reporters, a written pool report is distributed to all members. A pool spray is a brief photo opportunity, for instance, at the White House following a meeting.
Usage examples of "press pool".
If he was too dumb to remember that he was a member of the press pool pre-selected for Pentagon operations, it wasn't her lookout.
In this case it was a dinner for senior administration officials and selected members of the press pool.
The face he showed to the guests, to the few reporters who had picked winning tickets in the press pool lottery, was calm, warmly loving, dutiful.
The members of the press pool had been chosen by lot to cover the invasion story.