noun
A supplementary note or condition added to a document, often clarifying or qualifying the main content. Common in legal, business, or formal writing.
契約書になお書きを追加する。
Add a proviso to the contract.
なお書きには、返品条件が詳しく書かれている。
The explanatory note details the return conditions.
但し書き is a similar term meaning a proviso or conditional note, often used interchangeably with なお書き, but 但し書き can emphasize a restriction or exception.
Compound of なお (furthermore, in addition) and 書き (writing). The exact historical derivation is uncertain, but it follows a common pattern for forming nouns from verb stems.