The phrase "jacket pocket" refers to a small pouch or space on the front of a coat or jacket where you can store small items like keys, phones, or wallets. Full definition
If you're in the habit of dropping your phone in your front jeans pocket, or your inside jacket pocket, you'll immediately notice the difference. (slashgear.com)
This bag is very cute and perfect for a night out - especially in the summer when you don't have winter jacket pockets to hold your small items! (angelaroi.com)
A simple shirt or jacket pocket makes it super easy to reach in with one hand and pull out a card. (topresume.com)