# Lightning Network Glossary
Short definitions of terms you'll run into while using Lightning on your MyNode.
# A to C
# Alias
A public display name for your node. It isn't unique, so anyone can use the same one. See changing your LND alias.
# AMP
Atomic Multi-path Payment. A way to pay a node without an invoice, split across multiple routes. MyNode's default Lightning config accepts these payments.
# Anchor Channel
A channel type with small extra outputs, which let either side raise the fee on a force close after broadcasting it. LND keeps a small on-chain balance in reserve to pay for this.
# Base Fee
The flat part of a routing fee, charged per forward. LND's default is 1,000 millisats (1 sat).
# BOLT11
The standard format for a Lightning invoice.
# Capacity
The total size of a channel, counting both sides. See Lightning Basics.
# Channel
A shared balance between two Lightning nodes, secured by an on-chain 2-of-2 multisig output.
# Channel Reserve
A small part of a channel's balance, usually about 1%, that each side must keep and can't spend. It means a peer always has something to lose by cheating.
# Clearnet
The regular internet, as opposed to Tor. MyNode uses Tor by default.
# CLTV
CheckLockTimeVerify. A Bitcoin script feature that locks funds until a specific block height. Lightning uses it to give each hop in a payment time to react. The CLTV delta is how many blocks a node requires for that, and LND's default is 80.
# Commitment Transaction
The latest signed but unbroadcast transaction that holds a channel's current balance. Either side can broadcast it to force close the channel.
# Cooperative Close
Closing a channel with both peers' agreement. It's the cheapest and fastest way to close. See Closing Lightning Channels.
# CSV
CheckSequenceVerify. A Bitcoin script feature that locks funds for a number of blocks after a transaction confirms. It's what creates the wait after you force close a channel.
# D to K
# Data Loss Protection
A feature that lets a node that has lost its data ask its peers to close their channels. Channel recovery using an SCB depends on this.
# Force Close
Closing a channel without your peer's cooperation by broadcasting the latest commitment transaction. See Closing Lightning Channels.
# Gossip
How nodes share information about public channels and other nodes across the network.
# HTLC
Hash Time-Locked Contract. The building block of a Lightning payment. Funds on each hop are released when the receiver reveals a secret, or returned when a time limit passes. This makes multi-hop payments safe, since each hop either completes or refunds.
# Inbound Liquidity
The balance on your peer's side of a channel, which determines how much you can receive. See Inbound Liquidity.
# Invoice
A payment request created by the receiver. See Sending and Receiving Lightning Payments.
# Justice Transaction
A transaction that takes the entire balance of a channel when a peer closes it with an old state. Your node, or a watchtower, broadcasts it.
# Keysend
A payment sent directly to a node's public key, without an invoice. MyNode's default Lightning config accepts these payments.
# L to O
# Limbo Balance
Funds from a closing channel that are still locked or unconfirmed, and so aren't in your on-chain wallet yet.
# LND
Lightning Network Daemon. The Lightning node software that MyNode runs.
# LNDHub
A service that lets wallets like BlueWallet use accounts on your node.
# LNURL
A set of protocols that use a web server to simplify payments, for example with reusable QR codes and withdrawal links.
# Lightning Address
A payment address that looks like an email address, built on LNURL.
# Loop
A Lightning Labs swap service that moves funds between Lightning and on-chain. See Inbound Liquidity.
# LSP
Lightning Service Provider. A company that sells channels or liquidity to nodes and wallets.
# Macaroon
A credential that lets an app or wallet access LND with specific permissions. MyNode's Lightning page lets you download the admin, readonly and invoice macaroons. Treat the admin macaroon like a password, since it allows spending your funds. "Reset Macaroons" on the Settings page deletes them, and paired wallets stop working until you pair them again.
# Millisat
One thousandth of a satoshi (msat). Lightning tracks balances to this precision, though on-chain transactions only use whole sats.
# MPP
Multi-Path Payment. A single payment split into smaller parts that take different routes to the same destination.
# Node URI
Your node's full address, in the form pubkey@address:port. Other nodes use it to connect to you. It's shown on the MyNode Lightning page.
# Onion Routing
A method of encrypting payment details in layers, so each hop knows only the previous and next hop. It's related to, but separate from, Tor.
# Outbound Liquidity
The balance on your side of a channel, which determines how much you can send.
# P to S
# Peer
A node connected directly to yours, usually sharing a channel.
# Pool
A Lightning Labs auction marketplace for buying and selling channels. It's available through Lightning Terminal.
# PPM
Parts per million. The usual way to express a percentage routing fee. For example, 1,000 ppm is 0.1%.
# Private Channel
A channel that isn't announced to the network. Also called an unannounced channel. See Opening Your First Lightning Channel.
# Public Key
The unique identifier of your node, also called its pubkey. It's the first part of your node URI.
# Rebalancing
Moving funds between your channels to change their inbound and outbound balances. See Routing Node Basics.
# Route Hint
Information in an invoice that helps senders reach a node through a private channel.
# Routing Node
A node that forwards payments for others, usually to earn fees.
# Sat
A satoshi, the smallest on-chain unit of bitcoin. 100,000,000 sats equal 1 BTC.
# SCB
Static Channel Backup. A file that helps you recover channel funds after a failure, along with your seed. See Backing Up a Lightning Node.
# Seed Phrase
The 24 words that back up your LND wallet. Anyone with these words can access your on-chain funds. Keep them secret and offline.
# Submarine Swap
A swap between Lightning and on-chain funds, in which neither side can run away with the money. Loop uses this method.
# T to Z
# Timelock
A condition that prevents funds from being spent until a certain block or amount of time. CLTV and CSV are the two kinds used in Lightning.
# TLS Certificate
A file wallets use to confirm that they're connecting to your node securely. If you regenerate it from the Lightning page, you may have to pair your wallets again.
# UTXO
Unspent Transaction Output. A chunk of on-chain bitcoin that you can spend. Each channel is funded from one or more UTXOs.
# Watchtower
A service that monitors the blockchain for you and responds if a peer tries to cheat while your node is offline. See Lightning Watchtowers.
# Wumbo Channel
A channel larger than the standard limit of 16,777,215 sats. MyNode's default config doesn't turn this on.