What exactly is an open wallet and when do you need one?

I saw someone refer to an open wallet the other day and realized… I have no idea what that means. I’ve heard of hot wallets, cold wallets, non-custodial wallets—but open?

Is it just a term for wallets that support open standards like Web3 and EVM compatibility? Or does it refer to wallets where you can import/export keys freely?

I’m using MetaMask and a Ledger, and I think they’re considered open in the sense that I control my keys—but I’m not 100% sure.

Anyone know what “open wallet” really means in 2025 crypto lingo? Is it a security thing, an access thing, or just another buzzword?