Quick overview
This glossary explains terms you’ll see while using MetaMask and similar software wallets. Short definitions, practical examples, and links back to step-by-step guides make this useful whether you’re setting up on desktop or using your phone.
I use MetaMask daily for swaps, staking interfaces, and interacting with smart contracts. I’ve made mistakes (approved an unlimited token allowance once), so I keep the practical security tips front and center. And yes: read the seed phrase guidance carefully.
Core MetaMask terms
Seed phrase vs private keys
Seed phrase metamask: a human-readable list of words (typically 12–24) that recreates all your private keys for the wallet. Store this phrase offline. If someone gets it, they get control of your funds.
Private keys: the cryptographic secrets that sign transactions. MetaMask derives private keys from the seed phrase. Treat private keys like cash. Don’t paste them into websites.
Why both terms matter? Because backup options and recovery depend on the seed phrase, and on-chain signatures use the private keys.
What is a MetaMask account / wallet address?
What is a metamask account: an account in the wallet that holds addresses and private keys. One seed phrase can generate multiple accounts.
What is a metamask wallet address: the public address (hex string starting with 0x on EVM chains) you share to receive tokens. Think of it like your bank account number — public, but tied to private keys.
See more on creating and restoring accounts: create-account and restore-wallet.
Non-custodial & hot wallet explained
Non-custodial: you hold the private keys. MetaMask is non-custodial when you control the seed phrase.
Hot wallet: a wallet connected to the internet (browser extension or mobile app). Convenient for daily use, but higher attack surface than cold storage.
If you move sizable funds, consider combining MetaMask with a hardware device: connect-ledger.
Networks & multi-chain terms
EVM-compatible, RPC, and L2
EVM-compatible: blockchains that run the Ethereum Virtual Machine. MetaMask’s native strength is EVM-compatible networks (Ethereum, BSC-like chains, Polygon, Avalanche, Optimism, Arbitrum, etc.).
RPC (Remote Procedure Call): the API endpoint your wallet uses to read chain data and broadcast transactions. Custom RPC entries let you add networks manually: add-custom-network.
Layer 2 / L2: networks built on top of Ethereum to reduce gas fees (Optimism, Arbitrum, zk-rollups). Switching networks in MetaMask is like changing tabs in a browser — seamless when configured correctly. But watch which chain you’re sending from.
Want to add Polygon or BSC? See how-to-add-polygon and how-to-add-bsc.
DeFi & dApp interaction terms
WalletConnect, injected providers, and dApp browsers
WalletConnect: a protocol that connects mobile wallets to web dApps using QR codes or deep links. Use it when the dApp doesn’t accept your injected MetaMask or when using mobile: walletconnect-and-mobile-browser.
Injected provider: the JavaScript object a browser-extension wallet exposes to sites so dApps can request signatures.
dApp browser: the in-app browser some mobile wallets include to reduce friction. I prefer WalletConnect in many cases (less risky than pasting private keys into a dApp). And yes, always verify the URL.
Token allowance / token approval and revoke approvals
Token allowance (token approval): when you let a smart contract spend tokens on your behalf (for swaps, staking, or bridging). Many DeFi UIs request an "Approve". Approving unlimited allowances is common but increases risk.
Revoke approvals: the act of removing previously granted allowances. I revoke approvals after one-off trades. Use on-chain explorer tools or see our step-by-step: revoke-approvals.
I once approved an allowance for a test aggregator and then revoked it the same day — saved a potential loss.
Transactions, gas, and swap terms
EIP-1559, priority fees, and gas estimation
EIP-1559: fee model that splits gas into base fee (burned) and priority fee (tip to miners/validators). MetaMask exposes priority fee controls; pick higher fees for faster confirmation.
Gas estimation: wallets estimate gas but can be wrong when contracts have complex logic. If a transaction fails, check stuck-pending-transactions or transaction-error-debugging.
Built-in swaps & aggregator routing
- Built-in swap: an in-wallet feature that routes trades across DEXs to find better prices. It saves time but be mindful of slippage and the list of liquidity sources used (review the route before confirming). See details at built-in-swap.
Token and NFT terms
Token standards: ERC-20 for fungible tokens, ERC-721 and ERC-1155 for NFTs on EVM chains. For token management tips see token-management.
Spam tokens and hidden assets: wallets may list tokens automatically; hide spam tokens and only trust tokens with verified contracts. For NFTs, see nft-management for hiding and transferring collections.
Security, backup, and recovery terms
Seed phrase metamask backup: write the seed phrase on paper, store in a safe or split across locations using metal backups. Cloud backups are convenient but expose you to account compromise if your provider is hacked.
Social recovery / smart recovery: some wallets offer account abstraction or social recovery schemes — MetaMask has experimental smart account tooling via SDKs (see account-abstraction). But understand trade-offs before enabling any cloud or social recovery.
Phishing detection & transaction simulation: MetaMask includes phishing warnings; transaction simulation tools can show what a contract call will do before signing.
For backup workflows see: backup-and-recovery-options and hardware-best-practices.
Advanced wallet concepts
Smart contract wallets & account abstraction: these wallets can batch transactions, use session keys, and enable gasless UX. They often run on top of standard accounts. For developers: sdk-snaps-smart-accounts.
Session keys: temporary keys that limit risk for dApp sessions (allow only certain actions). Useful for daily use when you want fewer confirmations.
Bridges & cross-chain: built-in bridging features exist in some UIs, but bridging carries smart contract and counterparty risk. See bridges-cross-chain for specifics.
Quick comparison table: wallet types
| Feature |
MetaMask (extension + mobile) |
Mobile-only wallet |
Hardware + wallet (used via extension) |
| Non-custodial |
Yes |
Yes |
Yes (keys on device) |
| EVM-compatible support |
Native |
Often |
Dependent on client |
| WalletConnect support |
Mobile & dApps |
Native |
Via host wallet |
| Built-in swap |
Yes |
Often |
No (relay through wallet) |
| Hardware signing |
Supports Ledger/Trezor |
Some phones support keys |
Native |
How-to snippets & where to go next
FAQ
Q: Is it safe to keep crypto in a hot wallet?
A: Safer than an exchange if you control private keys, but a hot wallet is exposed to phishing and browser exploits. For significant holdings, pair MetaMask with a hardware wallet. See security-best-practices.
Q: How do I revoke token approvals?
A: Use the wallet's revoke tool or an on-chain approver UI to remove allowances. Confirm the contract address and revoke unlimited approvals. Step-by-step: revoke-approvals.
Q: What happens if I lose my phone?
A: If you have your seed phrase, restore on a new device using restore-wallet. If you don't — funds are likely lost. That’s why backups matter.
Q: What is a MetaMask account vs wallet address?
A: A MetaMask account houses a private key and its derived public address (the wallet address). Multiple accounts can live under one seed phrase. More: accounts-addresses.
Conclusion & next steps
This glossary translates the key terms that matter when using MetaMask and similar hot wallets. If you want to act now, follow the practical guides: install-extension for desktop setup or install-mobile for phones, and secure your seed phrase with steps at backup-and-recovery-options.
Want a focused walkthrough? Start with setup and then test small transfers before larger moves. But always verify contract addresses and revoke approvals after one-off permissions.
— Read the setup guides and the security checklist next: setup-desktop | setup-mobile | security-best-practices.
