Custodial vs Non-Custodial Wallet
Whether a third party (custodial) or the user alone (non-custodial) controls the private keys, and therefore the crypto.
Definition
In a custodial arrangement, a company such as an exchange or a crypto casino holds the private keys and thus controls user balances, offering convenience and password recovery but requiring you to trust the custodian's honesty, solvency and security. In a non-custodial (self-custody) wallet, only the user holds the keys and seed phrase, giving full control and censorship-resistance but full responsibility, since lost keys mean lost funds with no recovery. Depositing to a gambling site is typically custodial: the operator controls your funds until you withdraw, so operator insolvency or account freezes are a real risk.
Worked example
Money sitting in your casino account is custodial (the operator controls the keys); once you withdraw to your own seed-phrase-backed wallet, it becomes non-custodial.
Why it matters
The key trust distinction determining who can lose or freeze your funds; it is central to both self-custody safety and counterparty-risk assessment.