Yup, there's a difference!
As a cosmetic chemist, I get seriously peeved when I see a facial oil being described as 'hydrating'. But as a consumer, these words may not appear so different. Let's break it down.
Refers to something that increases the water content of the skin. For a product to be hydrating, it must contain water. It also usually contains humectants (ingredients that pull water into the skin), like glycerin, pentylene glycol, and hyaluronic acid.
Refers to something that prevents transepidermal water loss. Sound too scientific? Basically, moisturizing products support your skin barrier so it doesn't lose water that's already in your skin. For a product to be moisturizing, it must contain emollients and occlusive agents. These are oily feeling ingredients like natural oils and butters, and petrolatum (although we don't use petrolatum as it's not renewably sourced).
Here's my little diagram. If you're looking for hydration, check out Power Serum. In need of moisturization? Super Oil's your bff. And if you want something that does both... well you'll just have to wait until May ;)