The Difference between Waterproof & Showerproof

What is the difference between showerproof and waterproof?

If a garment is described as waterproof, it will be made from a waterproof fabric and the seams will be taped to ensure there is no water seepage through the seams.

Showerproof may mean that the fabric is not waterproof but has natural water repellency, sufficient for light showers.

More often it means that the fabric is waterproof, but the seams are not taped and so water will seep through the seams in heavy rain.

The reason for not taping seams is that it almost halves the labour costs so will make the item cheaper.