A short written note or memo used to record things to remember; a brief memorandum or personal/business note.
会議の後で、決まったことを覚書にまとめておきます。
After the meeting I'll summarize what was decided in a memo.
出張の予定は覚え書に書いて机の上に置いておいた。
I wrote the business trip schedule on a memo and left it on my desk.
ちょっとした連絡事項はメールではなく覚書で回すことにした。
We decided to circulate small notices as memos instead of by email.
A formal memorandum, especially in diplomatic contexts, recording agreements or understandings between parties.
両国は境界問題に関する覚書に署名した。
The two countries signed a memorandum regarding the border issue.
覚書の内容は外務省が公式に発表した。
The contents of the memorandum were officially announced by the foreign ministry.