To put it bluntly, negative space is the ‘space inbetween’, the area between or around other elements that form its own shape.
The widely regarded king and path-forger of negative space was artist M.C. Escher whose work I’m sure you’ve seen and been baffled by before. Escher did a number of tessellations that focussed on one shape leading into the next via negative and positive space, like this woodcut print “Sky & Water I”.
See how Escher has used the space in between the birds to create the shape of fish? This is negative space at work – considering everything around and in between your physical design, and manipulating that space to form something new.
Negative space when used strategically and cleverly can help create truly stunning and clever designs. Have a look at these simple animal icons by designer George Bokhua that use simple, clean shapes to render clear depictions of each animal.