Well, more an arrow slit, but it lets in light.

There are arrow slits dotted along the bottom of the remaining wall.

She saw a window above her, high and narrow, scarcely more than an arrow slit.

The windows were small or even only arrow slits.

The eastern and western sides each had 21 arrow slits.

Or maybe arrow slits would be more appropriate, Hayward thought.

In print news, your job is to know things about others; you peer out at the world through an arrow slit.

There were none on the ground floor, only slim arrow slits, too narrow to admit a person.

A thousand windows were visible from this direction alone, some huge, others no bigger than an arrow slit.

Fifty years ago they were little more than arrow slits but Will changed all that.