There is a subtle difference between waterproof and water-resistant jackets. Both types sometimes come with a DWR coating—durable water-repellent—which increases the water-resisting abilities.
Waterproof
Waterproof jackets are suitable for running in heavy downpours for extended periods. They are certified waterproof when they've reached a certain level of water-resistance in lab tests.
They are usually breathable, although they may be somewhat bulky and feel heavy when worn.
Water-Resistant
Water-resistant jackets are more common and suitable for lighter weather for shorter periods.
They're more lightweight and offer a better range of motion. However, they're not great for withstanding heavy rain.