Wallet

Software or hardware that manages your private keys and lets you sign transactions.

A wallet manages the cryptographic keys that control your on-chain accounts. Hot wallets (MetaMask, Phantom, Rabby) run on internet-connected devices and are convenient but exposed to malware. Hardware wallets (Ledger, Trezor) keep keys offline on a dedicated device and are the standard for material holdings. Smart contract wallets (Safe, Argent) replace single-signature keys with multi-sig and recovery mechanisms.

The phrase "not your keys, not your coins" refers to custodial accounts on exchanges. Tokens held on a centralized exchange aren't actually yours until you withdraw them to a wallet you control. FTX, Mt. Gox, and Celsius all proved this point expensively.