(~s)
1.
A ~ in a surface is a very narrow crack or opening in it.
...a ~ in the wall...
He peered through a ~ in the curtains.
N-COUNT: usu N in n
2.
A ~ of light is a small patch of light that shines through a small opening in something.
I noticed a ~ of light at the end of the corridor.
N-COUNT: N of n