a hole that a button is pushed through to fasten a shirt, coat, etc.

a flower that a man wears in the buttonhole of, or fastened to, his jacket on a special occasion such as a wedding

to stop someone and make them listen to you

Greg buttonholed me about sales figures when I came out of the meeting. 当我开完会出来时，格雷格拦住我跟我说了销售数据的事。