piece of paper; slip of paper; strip of paper; scrap of paper
メモを書いた紙切れをポケットに入れた。
I put the scrap of paper with the memo in my pocket.
紙切れ一枚の契約書は信用できない。
A contract on a single scrap of paper can't be trusted.
引き出しを開けると古い紙切れが何枚も出てきた。
When I opened the drawer, several old scraps of paper came out.