'friendly gathering' is correct and usable in written English.
You can use it to refer to any gathering of people that has a relaxed, friendly atmosphere. For example, "My family had a friendly gathering over the weekend to celebrate my grandfather's birthday."
By early afternoon there is a friendly gathering of four men, talking and watching the races.
Ursula's Diner is a friendly gathering place across from a waterfront park and boat launching area.
The Scene Ursula's Diner is a friendly gathering place across from a waterfront park and boat launching area.
Yesterday was my first time attending "A Company of Authors" – a warm and friendly gathering of about 100 or so booklovers at the Stanford Humanities Center.
The album contains a painting of the scene of the Kyehoe, a friendly gathering of literati or officials, and a list of the participants.
It had been the kind of friendly gathering when even someone's Golden Retriever wore a Seltzer sandwich board for a bit.
It is sung at family meals, friendly gatherings and in schools.
Strong-willed, fashionable, and full of spirit, she enjoyed life and all it had to offer, planning trips around the world and friendly gatherings at home.
During the Chosŏn period, officials often held friendly gatherings and commemorated the occasion by sharing the same copy of the painting of the scene.
I went back to Paul Graham's email, still seeking a guru who, under any pretext at all, would abolish from the workweek all but friendly gatherings and urgent meetings (to be run by Robert's Rules) in favor of long, fertile hours of solitude.
My two beautiful girls, the little house in Santa Monica, the California sunsets and constant friendly gatherings.
