Alternative trading system (ATS)
A US trading venue that matches buyers and sellers but registers as a broker-dealer under Regulation ATS instead of as an exchange. Dark pools in US equities operate as alternative trading systems.
Read: Dark pools
Crypto glossary: the trading floor, A to Z
Short, plain definitions of the words used on trading desks, in DeFi and in crypto regulation, each one linked to the guide that explains it in full.
In 30 seconds
This crypto glossary defines the crypto trading terms that come up across the guide, from order book and spread to MEV, MiCA and the CASP license. Each entry takes two sentences or fewer and links to the page where the idea is worked through with examples, diagrams and sources.
Market structure has its own vocabulary, and most of it was borrowed from equity trading floors long before bitcoin existed. Words such as midpoint, block trade and trade-through sit next to newer ones that only make sense on a blockchain, such as impermanent loss or MEV.
This crypto glossary keeps both in one list. The crypto trading terms are sorted A to Z, each with a short definition and a link to the guide that explains it properly, from order types to exchange licensing. Entries that name a law or a license carry their date, and legal statuses are given as of October 2026. Sixty-eight terms are listed in all.
A
Arbitrage
Buying an asset where it is cheaper and selling it where it is dearer at almost the same moment. Arbitrage traders pull prices on different venues back toward each other, which is one reason quotes rarely drift far apart for long.
Read: Market makersAsk (offer)
The lowest price at which someone in an order book is currently willing to sell. A buyer who wants an immediate fill pays the ask, and the gap between the ask and the bid is the spread.
Read: LiquidityAtomic swap
A trade of two assets, often on two different blockchains, built so that either both transfers complete or neither does. The swap removes the need to trust a counterparty or an intermediary to deliver its side.
Read: DEXsAutomated market maker (AMM)
A smart contract that quotes prices from a formula and the reserves held in a liquidity pool, instead of from an order book. Traders swap against the pool, and every trade shifts the price it quotes next.
Read: DEXsB
Basis point
One hundredth of one percent (0.01%). Spreads, fees and slippage are often quoted in basis points, so a 25 basis point spread on a $10,000 order works out to $25.
Read: SlippageBest execution
The duty of a broker to seek the most favorable result reasonably available for a client order. In the US it rests on FINRA Rule 5310, and in the EU on Article 27 of MiFID II.
Read: Best executionBid
The highest price at which someone in an order book is currently willing to buy. A seller who wants to trade at once receives the bid, so the bid side of the book absorbs market sell orders.
Read: LiquidityBitLicense
New York's license for virtual-currency business activity involving the state or its residents, issued by the Department of Financial Services under 23 NYCRR Part 200. The rule took effect on June 24, 2015.
Read: RegulationBlock trade
A single trade much larger than the usual order size on a venue. Block trades are often negotiated privately or matched in a dark pool, because showing them on a public order book would move the price against the trader.
Read: OTC tradingC
Crypto-asset service provider (CASP)
The EU term under MiCA for a firm that offers crypto services such as custody, exchange or running a trading platform. A CASP needs authorization from a national competent authority, then may passport that license across the EU.
Read: RegulationCentralized exchange (CEX)
A trading venue run by a company that holds customer assets, keeps the order book on its own servers and matches trades internally. Withdrawals to a wallet are the moment assets leave its custody.
Read: DEXsCLARITY Act
A US bill (H.R. 3633) to divide oversight of digital-asset markets between the SEC and the CFTC. It passed the House on July 17, 2025, but a Senate cloture vote failed on September 15, 2026, so it is not law as of October 2026.
Read: RegulationConcentrated liquidity
An AMM design in which each liquidity provider chooses a price range for its funds. Capital sits where trading actually happens, so the pool is deeper near the current price and thinner far away from it.
Read: LiquidityCounterparty risk
The chance that the other side of a trade fails to deliver the asset or the cash it owes. Counterparty risk matters most in bilateral OTC deals and on venues that hold client funds.
Read: OTC tradingCustody
Holding assets on behalf of someone else. On a centralized exchange the venue keeps custody of deposits; on a decentralized exchange traders keep their own keys and the smart contract settles the trade directly from their wallets.
Read: DEXsD
Digital Asset Business Act (DABA)
Bermuda's 2018 law for firms that issue, exchange, hold or trade digital assets, administered by the Bermuda Monetary Authority. It set out full and modified license classes, and the authority now also lists a test class.
Read: RegulationDAO Report
An SEC investigative report of July 25, 2017, which found that tokens sold by The DAO were securities. It made clear that federal securities laws can apply to token sales, whatever the technology behind them.
Read: ICO eraDark pool
A trading venue that does not display its orders before they execute. Buyers and sellers are matched privately, often at the midpoint of a public reference price, and the trade is reported only after it happens.
Read: Dark poolsDEX aggregator
A service that compares prices across several decentralized exchanges and splits one swap between them to reduce price impact. It works like a smart order router for liquidity pools.
Read: DEXsE
E-money token (EMT)
Under MiCA, a stablecoin that aims to hold a stable value by referencing one official currency, such as the euro. MiCA's rules for e-money tokens and asset-referenced tokens applied from June 30, 2024.
Read: RegulationF
Fill
The execution of an order, in whole or in part. A partial fill means only some of the requested quantity traded, and the rest either waits in the book or is canceled, depending on the order's instructions.
Read: Order typesFragmentation
The spread of trading in one asset across many separate venues. Each venue holds only part of the available liquidity, so a large order may need to visit several of them to fill at a fair price.
Read: Order routingFront-running
Trading ahead of a known pending order to profit from the price move it will cause. On public blockchains, waiting transactions are visible before they confirm, which makes a form of front-running technically possible.
Read: DEXsG
Gas fee
The fee paid to process a transaction on a blockchain such as Ethereum. On a decentralized exchange the gas fee is paid on top of the pool's trading fee, and it does not depend on the size of the trade.
Read: DEXsGENIUS Act
The US federal law for payment stablecoins, signed on July 18, 2025 as Public Law 119-27. It is expected to take effect by January 18, 2027, or earlier if final regulations arrive first.
Read: RegulationH
I
Initial coin offering (ICO)
A sale of newly created tokens to the public, usually paid for in bitcoin or ether. ICOs peaked in 2017, when token sales raised roughly $5 billion according to estimates that range from about $4.9 billion to about $5.3 billion.
Read: ICO eraIceberg order
A large limit order that shows only a small visible slice in the order book. When the slice fills, the next slice appears, so the full size of the order stays hidden from other traders.
Read: Order typesImpermanent loss
The shortfall a liquidity provider sees, compared with simply holding the two assets, when their relative price moves. It is called impermanent because it shrinks if prices return, and becomes real once the provider withdraws.
Read: LiquidityK
Know your customer (KYC)
Identity checks a regulated firm runs before it lets a client trade, such as verifying a name, address and source of funds. KYC sits alongside anti-money-laundering (AML) rules at exchanges and OTC desks.
Read: OTC tradingL
Limit order
An order to buy or sell at a stated price or better. A limit order that cannot trade at once rests in the order book and adds liquidity, but it may never fill if the market moves away.
Read: Order typesLiquidity
How easily an asset can be bought or sold without moving its price much. A liquid market has tight spreads and deep order books, so even a fairly large order changes the price only a little.
Read: LiquidityLiquidity mining
Paying liquidity providers or users in a protocol's own token as a reward for supplying funds or trading. Compound began distributing its COMP token this way on June 15, 2020, a moment often taken as the start of the informal DeFi Summer.
Read: LiquidityLiquidity pool
A pair or set of tokens locked in a smart contract that traders swap against. Liquidity providers deposit the tokens and earn a share of the trading fees in return for taking price risk.
Read: LiquidityLiquidity provider (LP)
Anyone who supplies the assets others trade against: a market maker posting quotes in an order book, or a depositor funding an AMM pool. Providers earn spreads or fees and carry the inventory risk.
Read: LiquidityLit market
A venue that displays its orders in a public order book before they trade, as most exchanges do. The term exists mainly to contrast with dark pools, where resting orders stay hidden.
Read: Dark poolsM
Maker-taker fees
A pricing model in which orders that add liquidity to the book (makers) pay a lower fee or earn a rebate, while orders that remove liquidity (takers) pay a higher fee.
Read: Market makersMarket depth
The quantity available to buy or sell at each price level beyond the best bid and ask. Depth shows how far the price would move if a large order swept through several levels of the book.
Read: LiquidityMarket maker
A firm or program that quotes both a buy price and a sell price and stands ready to trade at them. It earns the spread and carries the risk of holding inventory while prices move.
Read: Market makersMarket order
An order to buy or sell immediately at the best prices available. A market order guarantees a fill in a liquid market but not the price, so it can suffer slippage in a thin book.
Read: Order typesMatching engine
The software at the core of a trading venue that pairs incoming orders with resting ones. Most matching engines follow price-time priority: the best price trades first, and at the same price, the earliest order.
Read: Order typesMaximal extractable value (MEV)
The profit that block producers or bots can capture by reordering, inserting or excluding transactions in a block. On DEXs, MEV shows up as sandwich trades around a large swap that raise its cost.
Read: DEXsMiCA
The EU's Markets in Crypto-Assets Regulation, Regulation (EU) 2023/1114. It entered into force on June 29, 2023, applied in full from December 30, 2024, and its transitional period for existing firms ended by July 1, 2026 at the latest.
Read: RegulationMidpoint
The price halfway between the best bid and the best ask. Many dark pools match orders at the midpoint, so buyer and seller each save half the spread compared with crossing it on a lit venue.
Read: Dark poolsN
National best bid and offer (NBBO)
In US equities, the highest bid and the lowest offer across all exchanges, published as one consolidated quote. Crypto has no official equivalent, so each venue chooses its own reference price.
Read: Best executionO
Off-exchange trading
Trading that happens away from public exchanges: in dark pools, with wholesalers or on single-dealer platforms. Off-exchange is a wider category than dark pools, which are only one part of it.
Read: Dark poolsOrder book
The live list of resting buy and sell orders on a venue, sorted by price. The top of the book shows the best bid and ask, and the levels below show the depth behind them.
Read: LiquidityOrder Protection Rule
Rule 611 of the SEC's Regulation NMS, adopted in 2005. It requires US equity trading centers to keep policies that prevent trades at prices worse than a protected quote shown on another venue.
Read: Order routingOTC desk
A dealer or broker that arranges large trades directly with clients instead of through a public order book. Prices are quoted on request, and settlement is agreed between the two sides.
Read: OTC tradingP
Passporting
The right of a firm authorized in one EU member state to offer the same services across the whole EU. Under MiCA, a CASP authorization can be passported without a fresh license in each country.
Read: RegulationPeg order
An order whose price follows a reference price automatically, such as the best bid, the best ask or the midpoint. A midpoint peg order is the basic building block of most dark pool matching.
Read: Order typesPrice impact
How far an order itself moves the market price as it fills. In an AMM pool, price impact depends on the trade's size relative to the pool's reserves; in an order book, on the depth at each level.
Read: SlippageR
Regulation NMS
The SEC's 2005 set of rules for the US national market system in equities. It includes the Order Protection Rule against trade-throughs and shaped how brokers route orders between competing exchanges.
Read: Order routingRequest for quote (RFQ)
A trading method in which a client asks one or more dealers for a price on a stated size, then accepts or rejects the quotes. RFQ is the usual way OTC desks price block trades.
Read: OTC tradingS
Settlement
The final transfer of the asset to the buyer and the payment to the seller after a trade is agreed. On a blockchain settlement can be the trade itself; in OTC deals it is a separate step.
Read: OTC tradingSlippage
The difference between the price a trader expected and the average price actually received. Slippage comes from price impact, from the market moving while the order is in flight, or from both together.
Read: SlippageSlippage tolerance
A limit, set in percent, on how much worse than the quoted price a DEX swap may execute. If the final price falls outside the tolerance, the transaction fails instead of filling at a poor price.
Read: SlippageSmart order router (SOR)
Software that splits an order across several venues and sends each piece where the price, fees and available size are best at that moment. Routers are a direct response to fragmented liquidity.
Read: Order routingSpread
The gap between the best bid and the best ask in a market. A narrow spread signals a liquid market, and the spread is the basic cost a trader pays to buy and sell straight away.
Read: LiquidityStablecoin
A token designed to keep a steady value, usually one US dollar or one euro, backed by reserves or managed by a protocol. In the EU and the US, stablecoins now have their own dedicated rules.
Read: RegulationStop-limit order
An order that becomes a limit order once the market reaches a trigger price (the stop). It caps the execution price, but in a fast move the order may not fill at all.
Read: Order typesT
Time in force
The instruction that says how long an order stays active: good till canceled, for the day, immediate or cancel, or fill or kill. It decides what happens to any part of the order that does not trade at once.
Read: Order typesTrade-through
A trade executed at a price worse than a better quote displayed on another venue at the same moment. US equity rules prohibit most trade-throughs of protected quotes; crypto markets have no such rule.
Read: Order routingTransaction cost analysis (TCA)
Measuring what a trade really cost against a benchmark, such as the arrival price, the midpoint or VWAP. TCA counts fees, spread, price impact and delay, and it is the usual evidence for best execution.
Read: Best executionV
Volume-weighted average price (VWAP)
The average price of an asset over a period, weighted by how much traded at each price. VWAP is a common benchmark in transaction cost analysis and a target for large orders spread over time.
Read: Best executionW
Wash trading
Buying and selling the same asset with oneself, or with a coordinated partner, to create fake volume. Wash trading makes a market look more liquid than it is and is prohibited in regulated markets.
Read: Market makersWhitepaper
A document in which a crypto project describes its design, token and plans, usually published before a token sale. In the ICO era the whitepaper often served as the main or only disclosure document.
Read: ICO eraHow to use this glossary
Every entry ends with a link to one guide. The definition here is the short version; the guide is where the term is worked through with an illustrative order book, a diagram and the primary sources behind any rule it mentions. A reader who meets price impact here and wants the arithmetic can follow the link to the slippage guide and try the calculator there.
The links also run the other way. Inside each guide, one key word is set apart as a small postcard. The postcard repeats the definition in a sentence and points back to this page, landing on the exact entry, so /glossary#midpoint opens on the midpoint card.
The letter rail above the list jumps straight to a letter, and it stays pinned to the top of the screen while the list scrolls. The page remembers the last letter opened in the browser's local storage, under the name omega-glossary, so a return visit starts where the previous one stopped; the cookie policy lists exactly what is stored.
Terms tied to a law or a license carry their date. Rules change, and an entry that describes the CLARITY Act or MiCA reflects the state of things as of October 2026.
Short answers
Crypto trading terms FAQ
What are the most common crypto trading terms?
The crypto trading terms that come up most often are bid, ask, spread, order book, market order, limit order, liquidity and slippage. Together they describe who wants to trade, at what price, and how much the price moves when an order fills. Most other vocabulary in crypto market structure builds on these eight ideas.
What is the difference between a limit order and a market order?
A market order trades immediately at the best available prices, so it is sure to fill in a liquid market but the final price is not fixed. A limit order names a price and trades only at that price or better. It may rest in the order book for a long time, or never fill at all.
What does slippage mean in crypto trading?
Slippage in crypto trading is the gap between the price a trader expected and the average price actually received. It grows with order size relative to market depth and with how fast the market moves. On decentralized exchanges, a slippage tolerance setting cancels the swap if the price slips further than the trader allowed.
What is a dark pool in crypto?
A crypto dark pool is a trading venue that keeps orders hidden until they execute. It is used mostly for large trades, which are often matched at the midpoint between the best bid and ask on public venues. Crypto has no consolidated quote like the US NBBO, so each dark pool defines its own reference midpoint.
What is the difference between an AMM and an order book?
An order book matches individual buy and sell orders that traders post at prices they choose. An automated market maker has no orders: a smart contract quotes a price from a formula and the reserves in a liquidity pool, and every swap trades against those reserves, moving the quoted price as it goes.
Why do the definitions in this glossary link to other pages?
Each definition in the Omega.one glossary is kept to one or two sentences, which is enough to recognize a term but not to understand how it works in practice. The link leads to the guide that explains the mechanism with an illustrative example, a diagram and the primary sources for any rule or date it mentions.
Sources
- Investor.gov: Alternative trading systems (ATSs)
- SEC: Regulation NMS final rule (2005)
- FINRA Rule 5310: Best Execution and Interpositioning
- EUR-Lex: Regulation (EU) 2023/1114 (MiCA)
- NYDFS: Virtual currency businesses (BitLicense)
- Bermuda Monetary Authority: Digital asset business
- SEC: Report of Investigation on The DAO (2017)
- Congress.gov: S.1582, GENIUS Act
- Nasdaq: Midpoint Peg Post-Only factsheet
- Uniswap documentation