In colloquial Western Canadian English, a gaggle is an adjective describing a largely disorganized group of Jildos (another colloquial adjective describing a woman that tends to be annoying and lacking in her own individual opinions) putting forth discontent among all related fellows.
In the field of systems biology, The Gaggle is an open source software framework for exchanging data between independently developed software tools and databases to enable interactive exploration of data.
A "press gaggle" (as distinct from a press conference or press briefing) is the nickname given to an informal briefing by the White House Press Secretary which (as used by press secretaries for the George W. Bush administration) is on the record, but disallows videography. The term can also be used to refer to the informal interactions between the press and the press secretary that occur before a videotaped press briefing.
One former member of the White House Press Corps provided the following historical context:
The nickname is thought to stem from the idea that these more freewheeling press sessions, where the talk is much more rapid and free-form, are like a "gaggle of geese" honking. For example, the blog maintained by Newsweek magazine's political reporters is called The Gaggle; on their main page, their definition for "gaggle" when used to refer to the Washington, D.C. press, is "a flock of reporters pecking at a politician.