This skirt has a slit on the side.
slitting; cutting into strips
Industrial process of cutting wide rolls of material (paper, metal, film) into narrower strips.
The steel sheets that had undergone slitting were delivered.
There's a slit in the back of the skirt.
At the factory, rolled film is slit into narrower strips to make the final product.
The designer added a slit to the skirt.
This skirt has a deep slit that makes it easy to move in.