A rough outline or gist — the main points or a brief summary; can also be used adverbially to mean 'briefly' or 'in outline'.
会議の概略を参加者に配布した。
I distributed a brief outline of the meeting to the participants.
概略を述べると、今回の問題は予算の不足が原因です。
To put it briefly, the problem this time is due to a lack of budget.
報告書の冒頭に事業の概略を載せてください。
Please include an outline of the project at the beginning of the report.