A reunion or meeting again; often used for meeting after a long separation (commonly used with 'suru' to make a verb).
旧友と再会して昔話に花が咲いた。
I reunited with an old friend and we chatted about old times.
再会の約束をして別れた。
We parted after promising to meet again.
再会の場には多くの人が集まった。
Many people gathered at the reunion.