Open the door a crack.
We managed to squeeze through a crack in the rock wall.
Word: "crack"
the same meaning

I may be an hour.
When will the meeting be?
Word: "be"
different meanings

The sun sets, and the workers go to their rest.
I need to get a good rest tonight; I was up late last night.
Word: "rest"
the same meaning

It just won't make much of a difference to anyone.
It just won't make much difference to me.
Word: "difference"

the same meaning