noun · a black game piece or stone used in board games such as Go or Chinese chess

他在棋盘上放下一枚黑子。

noun · a temporary dark spot on the surface of the sun caused by intense magnetic activity

太阳黑子的活跃程度会影响地球的通讯。

noun · (slang) hater; detractor

别理会那些网络黑子。