If you're new to Cardano or to blockchains in general, you've probably come across a lot of unfamiliar words, such as "staking" and "eUTxO". This glossary explains the core terms you'll meet in Cardano wallets, DApps and guides, in plain language.
Core Concepts
Blockchain:
A blockchain is a digital ledger that many computers keep copies of. It records transactions in blocks, and each block is linked to the one before it, so changing an old record would break every link after it and the other computers would notice.1 For a longer introduction, see what is blockchain.
Block:
A block bundles a set of transactions and adds them to the chain together. Each block carries a cryptographic reference to the block before it. On Cardano, stake pools produce blocks, and the Ouroboros protocol decides which pool produces each one.2 A new block arrives about every 20 seconds on average.3
Node:
A node is a computer running Cardano's node software. Nodes connect to each other, pass along new blocks and transactions, and check that transactions follow the rules.3 Nodes play different roles:
- Relay nodes connect to the wider network and pass blocks and transactions to and from a stake pool's block producer, which stays hidden behind them.4
- Block-producing nodes create new blocks. Stake pool operators run them.4
- Full-node wallets such as Daedalus download the whole blockchain and check every transaction themselves, instead of trusting someone else's server.5
Cardano (ADA):
Cardano is an open-source Layer 1 blockchain whose protocol designs were published and peer reviewed before being built. Anyone can use it without asking permission.6 ADA is its native cryptocurrency. You use it to pay transaction fees and to delegate to stake pools, and the ADA you hold counts as voting power in governance. ADA is named after Ada Lovelace, the 19th-century mathematician, and Cardano after the 16th-century mathematician Gerolamo Cardano.7,6 To see what the network offers, read why Cardano.
Lovelace:
The smallest unit of ADA. 1 ADA = 1,000,000 lovelace. The blockchain stores every ADA amount as a whole number of lovelace, and wallets convert it to ADA for display.8
Wallet:
A wallet is an app or device that holds your private keys and lets you send, receive and manage ADA, tokens and NFTs. Your funds are recorded on the blockchain, not inside the app, which is why a different wallet can open the same funds.9 Wallets also connect to DApps (see CIP-30 below). To choose and set one up, see how to set up a Cardano wallet.
Seed Phrase (Recovery Phrase):
A list of words, usually 15 or 24 on Cardano, that your wallet shows you when you create it. Every private key in the wallet is derived from it, so it is all you need to restore your funds on a new device. It also means anyone who learns the phrase can take your funds. Write it on paper or metal, keep it offline, and never type it into a website or give it to anyone who asks, including "support" staff.10
Proof of Stake (PoS):
A way for a blockchain to agree on new blocks in which the chance to produce a block depends on how much cryptocurrency stands behind a participant, not on computing power. On Cardano, ADA holders delegate their stake to pools. The ADA stays in their wallets and is never locked, and none of it can be taken away as a penalty (known as slashing on some other chains).11
Ouroboros:
The set of related proof-of-stake protocols that keep Cardano's nodes in agreement about the chain. Each version comes with mathematical proofs of its security. Because it picks block producers by stake rather than by computing power, it uses far less energy than proof-of-work mining.12 Cardano mainnet currently runs Ouroboros Praos, which privately picks the pool that produces each block.13 Pools with more stake are picked more often.3
Self-Sovereign Identity (SSI):
An approach to digital identity in which you hold and control your own identifiers and credentials, instead of a company or government holding them for you. SSI tools often use decentralized identifiers (DIDs), which you create yourself with no central registrar. The records behind a DID live on a blockchain or a similar shared network.14,15 Identity projects on Cardano are listed in Adastack's identity category.
On-Chain:
Data, actions or contracts recorded directly on the blockchain, where anyone can check them. Once other blocks have been added on top of a transaction, it cannot be removed or reordered without every node noticing.3 The opposite, off-chain, means something happens outside the blockchain, for example on a website's server or on a Layer 2.
Epoch:
A five-day period on Cardano, made up of 432,000 one-second slots.3 During each epoch, the amount of stake behind each pool is fixed and used to calculate rewards, which are paid out two epochs later.16
Slot:
A one-second window of time. Each slot is a chance for a stake pool to be picked to make a block. Most slots pass with no block, which is why a block arrives about every 20 seconds on average.3
Smart Contract and Development Terms
Smart Contracts:
Programs stored on a blockchain that run automatically when a transaction meets the conditions they set.17 On Cardano, smart contracts power DApps such as exchanges and lending apps, so people can trade or borrow without a middleman holding their funds. Developers write them in languages such as Aiken, Plinth (based on Haskell) and OpShin (based on Python).18 Whatever the language, the contract is compiled to Plutus Core, the low-level code that Cardano nodes actually run.19
Plutus:
The name for Cardano's smart contract platform. When a transaction tries to spend funds locked by a script, Plutus checks that the transaction meets the script's rules. Every Cardano smart contract runs as Plutus Core, no matter which language it was written in.19
Plinth:
A language for writing Plutus smart contracts, formerly called Plutus Tx. Developers write contract logic in Haskell, within limits Plinth sets, and compile it to Plutus Core.20
Aiken:
A smart contract language made for Cardano, with its own compiler and built-in testing. The Cardano Developer Portal suggests it for most new projects.18 For where to start, see the intro to Cardano development.
DApp (Decentralized Application):
An application whose core rules run as smart contracts on a blockchain instead of on one company's servers. You usually reach a DApp through a normal website, but that site is only a window. The swap, loan or vote itself is carried out by on-chain code that keeps working if the website shuts down.21 Cardano has DApps for trading, lending, identity, gaming and more. See what is a DApp.
CIP (Cardano Improvement Proposal):
A public document that proposes a standard, feature or change for Cardano. Proposals are written and debated in the open, and the accepted ones become the standards that wallets, tools and protocol upgrades follow.22 All CIPs are published on the CIP website.
CIP-30:
The standard behind the "Connect Wallet" button on Cardano DApps. Read the CIP-30 specification for the technical detail. When you connect, your browser wallet asks for your permission. Once you approve, the site can read your addresses and send transactions to your wallet for you to sign. Your wallet does the signing on its own side of the connection; the website only receives the signed result. A follow-up standard, CIP-95, lets wallets also sign governance transactions such as votes and DRep registration.23
DEX (Decentralized Exchange):
A DApp for trading tokens where each swap runs as a smart contract. Your funds stay in your own wallet until the swap goes through; no exchange company holds them.24 Examples on Cardano include Minswap and SundaeSwap. More are listed in Adastack's DEXs category.
eUTxO (Extended Unspent Transaction Output):
Cardano's accounting model. It builds on the UTXO model that Bitcoin uses, where funds sit in separate outputs that work like banknotes: you spend a whole output and get change back as a new one.25 Cardano extends this so an output can also carry data and a script that sets the rules for spending it. Because a transaction depends only on the outputs it spends, you can check whether it will succeed before you submit it.26
Layer 1:
The blockchain that everything else is built on. It runs the consensus protocol, holds the ledger and gives transactions their final settlement. Cardano is a Layer 1.27
Layer 2:
A system that handles transactions outside the Layer 1 and settles the results back onto it, so the base chain's rules stay untouched.27 Cardano's main example is Hydra. A small group of users opens a "Hydra Head", makes fast transactions among themselves off the main chain, and later writes the final result back to Cardano. Hydra reached version 1.0 in October 2025.28 See what are Layer 2s.
Partner Chain:
A separate Layer 1 blockchain that runs alongside Cardano and connects to it. Midnight, a privacy-focused blockchain, is the example so far. It keeps its own ledger, and its transactions are not rolled up onto Cardano the way a Layer 2's are. It draws on Cardano's security and existing DApps, and its NIGHT token exists on both networks.29 See what are partner chains.
Staking & Governance
Staking:
On Cardano, staking means delegating your ADA to a stake pool to help run the network and earn rewards. Your ADA stays in your wallet: it is not locked, there is no minimum amount, nothing is slashed, and you can spend it at any time.30 Since the Plomin hard fork in January 2025, you also need to delegate your voting power to a DRep, or choose Abstain or No Confidence, before you can withdraw your rewards.31 For the steps, see how to stake ADA.
Stake Pool:
One or more servers that run Cardano's node software and produce blocks. ADA holders delegate to pools, and the more stake a pool has, the more often it is picked to produce a block. Each block earns rewards, which the pool shares with its delegators after taking its fees.32
Stake Pool Operator (SPO):
The person or team that runs a stake pool. SPOs keep their nodes online and secure, renew the pool's signing keys on schedule, and register the pool on-chain with a 500 ADA deposit that is returned when the pool retires.33 They take a fixed fee each epoch plus a margin, a percentage of the remaining rewards, before the rest goes to delegators.32 SPOs also vote on some governance actions, including hard forks and motions of no confidence.34
Delegation:
Assigning the stake of your ADA to a stake pool without sending the ADA anywhere. You keep full control of your funds, and the pool uses your stake's weight to win the right to produce blocks.35 Delegating to a pool and delegating your voting power to a DRep are separate choices, and you can make both with the same ADA.36
DRep (Delegated Representative):
A registered ADA holder who votes on governance actions for everyone who delegates voting power to them. Any ADA holder can become a DRep by registering with a 500 ADA deposit, which is returned when they retire.36 Any holder can delegate to a DRep and change that choice at any time.37 Instead of a DRep, you can also choose Abstain or No Confidence.36 To compare DReps, use the GovTool DRep directory.
Voltaire:
The fifth phase of Cardano's roadmap, focused on handing governance and the treasury to the community. Its on-chain rules went live with the Chang hard fork in September 2024.38
Hard Fork:
An upgrade to the protocol rules that old node software cannot process. Node operators install the new version ahead of time, and the switch happens at an agreed epoch.39 Cardano names its hard forks: Chang (September 2024) and Plomin (January 2025) together turned on on-chain governance.38,31
Governance:
How decisions about Cardano's future are made. Since the Chang and Plomin hard forks, decisions are made on-chain. Anyone can submit a proposal, called a governance action. Three groups vote on it: DReps, SPOs and the Constitutional Committee, though not every action needs all three. Once the required groups approve, the ledger applies the change itself; nobody has to carry it out by hand.40 For how voting works, see what is Cardano governance.
Governance Action:
A proposal recorded on the blockchain and put to a vote, such as a protocol parameter change, a treasury withdrawal or a change to the constitution.40 Submitting one takes a deposit of 100,000 ADA, returned when the action is enacted or expires.41
Constitutional Committee:
Seven elected members whose job is to say whether a governance action is allowed under the Cardano Constitution. Their approval is needed for most action types. The committee cannot submit actions itself, and a successful motion of no confidence by DReps and SPOs replaces it.42
Treasury:
A fund of ADA held by the protocol to pay for Cardano's development. Every epoch, 20% of the reward pot, which is made up of transaction fees plus ADA released from reserves, goes into it. Spending from it requires a treasury withdrawal that DReps and the Constitutional Committee approve.43
Project Catalyst:
Cardano's community grant program, started in 2020. In its first 14 funding rounds, ADA holders voted on which proposals received money from the treasury. The Cardano Foundation took over the program in 2026, and the planned Fund15 and Fund16 rounds were cancelled. Any new treasury money for Catalyst now needs a treasury withdrawal approved through on-chain governance.44 The Foundation's 2026 pilot round had no public vote: community curators narrowed the applications, then a 35-person review panel scored them and 12 teams were chosen.45 See what is Project Catalyst.
Cardano Constitution:
The document that sets the principles and rules for Cardano governance. It defines the roles of DReps, SPOs and the Constitutional Committee and sets limits on parameter changes and treasury spending, some of which a script enforces on-chain. Written through community workshops and a constitutional convention, it was ratified on-chain by DReps in February 2025, and an amended version has applied since January 2026.46 You can read the full constitution on the Cardano website.
Assets, Tokens, and NFTs
Native Tokens (Native Assets):
Tokens that Cardano's ledger supports directly, in the same way it handles ADA, so creating or sending one needs no smart contract. Native tokens arrived with the Mary hard fork.47
Policy ID:
The unique ID of a token's minting policy, the rules that say who can create or destroy that token and under what conditions. Two tokens may share a name and still be separate assets, because each has its own policy ID. Checking the policy ID is how you tell a real token or NFT from a copy.48
Minting:
Creating new tokens or NFTs on the blockchain. The token's minting policy decides who may mint it and when. Burning is the reverse: destroying tokens.48
Stablecoin:
A cryptocurrency designed to keep a steady value against a reference asset, usually a currency such as the US dollar. Some are backed by money held in reserve, others by crypto locked up as collateral, and if the backing fails, the price can drift away from its target. On Cardano, USDM is backed by fiat currency, while Djed is backed by a reserve of ADA worth more than the coins issued.49 More are listed in Adastack's stablecoins category.
NFT (Non-Fungible Token):
A token that stands for one unique item, such as artwork, a collectible or a credential. Copies of the image are easy to make, but the token itself sits in only one wallet at a time. On Cardano, an NFT is a native token with a supply of exactly one, under a minting policy that blocks any further minting.50 See what are NFTs.
More Cardano Glossaries
New terms appear as Cardano changes. For words not covered here:
- Cardano.org glossary: Open-source glossary on the Cardano website, with many more protocol, staking and governance terms
- Cardano vocab: More glossaries listed on Adastack
