also: ペーパーウエイト · ペーパーウェート · ペーパーウエート
A small heavy object placed on top of papers to keep them from scattering. The Japanese synonym 文鎮 (ぶんちん) is also common.
See also: 文鎮
I put a paperweight on the documents on my desk so they wouldn't blow away in the wind.