noun, noun which may take the genitive case particle 'no'
registered mail; registered post; mail registration
Only when written 書留
An abbreviation of 書留郵便. Commonly used with で送る, as in sending important documents by registered mail; can also modify a following noun with の.
See also: 書留郵便
大事な書類は書留で送ってください。
Please send the important documents by registered mail.
I bought a registered-cash-mail envelope at the post office.
noun
writing down; written record; registry
Only when written 書き留め / 書留め
Refers to the act or result of noting something down or putting it on record. As a standalone noun this is less common than the verb 書き留める or the noun 記録, but It is a noun.
机の上に電話番号の書き留めが残っていた。
A written note of the phone number was left on the desk.
会議の要点の書き留めを後で見直した。
I later reviewed my written notes of the meeting's main points.