The phrase "empty space" refers to an area or place that has no objects, things, or matter in it. It is completely vacant or devoid of any substance or physical presence. Full definition
Standard muffin pans come in 6 - or 12 - cup size; if baking 6 items in a 12 - cup pan, leave empty space in between. (marthastewart.com)
The omission of writing space is a huge advantage in saving ink and paper, because original papers comes with a lot of empty space for the answer. (tes.com)
And of course I picked the spot with empty spaces on either side to add to the illusion of safety. (comedyguys.com)