'granddaughter gathering' is correct and can be used in written English.
You could use it to refer to a gathering of multiple generations of the same family, usually for a special event such as a reunion. For example: "We had a special granddaughter gathering at Thanksgiving to celebrate my granddaughter's graduation."
He had walked about one and a half miles from his home in the Dokki neighborhood to be part of Tuesday's grand gathering in Tahrir Square.
The Governors Ball Music Festival is a grand gathering of some of the top names in pop and hip-hop music today.
Mr Karzai has announced that a loya jirga, a traditional grand gathering of the country's power-brokers, will be convened to decide on the Americans' future.
The vision is for a grand gathering of bishops, theologians, religious women and men and laypeople, as well as Vatican representatives.
The "grand gathering" has been called to debate the proposed Bilateral Status Agreement between the U.S. and Afghanistan, which would allow American forces to remain in the country after 2014.
Another plan would be to call a loya jirga, the traditional grand gathering of Afghanistan's power-brokers, which could chose a new leader and perhaps amend the constitution with an eye to holding fresh elections some time in the future.Both plans would merely extend the country's protracted period of political limbo.
Regularly invited to grand gatherings such as those of the G8 and G20, he has often been deemed "the voice of Africa".
The less good news is that it is far from clear what the latest in the series of un grand gatherings on saving the planet will achieve.
Then, as I'm not planning to have grand gatherings, I shortened the living room so I could make my bedroom larger and have room for a desk".
We are reminded of Alan Hollinghurst's The Line of Beauty, as though all wealthy Tories inevitably have grand gatherings with deep undercurrents of class, ambition and financial chicanery.
It really will be a grand civic gathering space".
