pen someone in/up
phrasal verb with pen verb [ T ] formal uk/pen/ us/pen/ -nn-
把…圈起来;把…关起来
to keep people or animals in a small area
The sheep were penned in behind the barn. 羊群被圈在谷仓后面。
The soldiers were penned up in their barracks. 士兵们被关在兵营里。