The meaning of a 4x4 closure wig is the lace size of a wig is 4x4 inches, 4 inches across, and 4 inches up and down. Once you noticed this size wig, it always refers to a square-shaped lace front wig. This allows you to part 4 inches across and 4 inches back and forth. This is a beginner's wig unit and it is recommended for women who love to take their wig off and put it back on.