alumni association; graduates' association; alumni meeting; class reunion
同窓会で旧友に再会した。
I reunited with an old friend at the reunion.
高校の同窓会で昔の写真を見て盛り上がった。
We had a great time looking at old photos at the high school reunion.
同窓会の幹事を引き受けたので、会場探しに苦労した。
I took on organizing the reunion, so finding a venue was a struggle.