The phrase 'formal gathering' is correct and can be used in written English.
It is used to describe an event or meeting that is structured, orderly, and possibly quite formal, often requiring dressy or semi-formal attire. For example, "She was invited to a formal gathering at the ambassador's house."
A cloud of tedium hangs over any formal gathering that ventures to discuss the thing.
Mr. Lew will join Mr. Obama on Saturday night for annual Alfalfa Club dinner, a formal gathering of Washington elites at which presidents traditionally speak.
Less than seven weeks before its convocation, it has at last deigned to announce a provisional date for its biggest formal gathering in five years.
Their leaders have conducted informal discussions before, but the event on Tuesday in the central Russian city of Yekaterinburg will mark their first formal gathering, officials said.
The formal gathering set to ratify China's accession, scheduled for Doha, Qatar, in November, seems likely to be relocated and perhaps postponed because of security concerns.
The formal gathering in Berlin -- or at some nearby venue, as yet unspecified -- was to be limited to about 30 Afghans, in line with Mr. Brahimi's insistence that any nascent administration be perceived as "homegrown".
We've done a number of less formal gatherings over the years, but this was the first time we had ever gathered everyone for a focused session with a structured agenda.
These bars support the thriving local music scene, hosting gigs and less formal gatherings.
There also are two smaller open-air dining areas that he uses for less formal gatherings.
Other, more formal gatherings include the Intern Welcome Party, Alumni Networking and Career Night, and the Senior Graduation Party.
Friends say he cooks primarily for the Obamas, while the executive chef, Cristeta Comerford, handles most formal gatherings.
