Trading Glossary

S

SAFT (Simple Agreement for Future Tokens)

An investment contract granting the right to receive tokens upon a future network launch.

Sanctions Screening

Checking customers, counterparties, and addresses against government sanctions lists.

Sandwich Attack

Placing one transaction before and one after a victim's trade, profiting from the price movement the victim causes. The principal reason to set conservative slippage tolerance.

Satoshi (sat)

The smallest denomination of Bitcoin: one hundred millionth of a BTC.

Scalability Trilemma

The observation that blockchain designs face trade-offs between decentralization, security, and scalability, and that optimizing all three simultaneously is the central engineering challenge of the field.

Schnorr Signature

A signature scheme offering simpler proofs, linearity, and native aggregation of multiple signatures. Introduced to Bitcoin via the Taproot upgrade.

SDN List

OFAC's list of Specially Designated Nationals, which includes designated blockchain addresses.

Searcher

A party that identifies profitable transaction ordering opportunities and submits bundles to builders.

secp256k1

The specific elliptic curve used by Bitcoin, Ethereum, and many other chains.

Security Token

A token that represents an investment contract or traditional security and is therefore subject to securities regulation. Classification is jurisdiction-specific and should never be asserted casually.

Security Token Offering (STO)

A token sale conducted under securities regulations.

Security vs. Commodity Classification

The determination of which regulatory regime and which regulator applies to a given asset. Outcomes vary by jurisdiction and remain actively contested; classification statements should always be made by qualified counsel rather than asserted in marketing or support material.

Seed Phrase / Recovery Phrase / Mnemonic

A human-readable sequence of words (typically twelve or twenty-four) encoding the master secret from which all of a wallet's keys are derived. Anyone with the phrase has complete control of the wallet.

Segregated Account

An account holding a single client's assets separately, improving bankruptcy-remoteness.

Segregation of Client Assets

The requirement to hold customer assets separately from corporate assets.

Selective Disclosure

Revealing specific information to a specific party without making it public. The design goal underpinning most compliance-compatible privacy work.

Self-Custody

The practice of holding one's own keys, accepting both full control and full responsibility.

Semi-Fungible Token

A token that is fungible within a class but distinguishable across classes.

Sequencer

The party responsible for ordering transactions on a rollup before they are committed to the underlying chain. Sequencer decentralization is an active area of development across the industry.

Ser / Wen / Fren

Deliberate misspellings used as community in-group markers ("wen token," "wen listing").

Session Key

A temporary, scope-limited key granting an application permission to act within defined constraints, removing the need to approve every action.

Settlement

The final transfer of assets completing a trade.

Settlement Layer

The component that finalizes state and resolves disputes.

SHA-256

The hash function used in Bitcoin's proof-of-work and address derivation, producing a 256-bit output.

Shamir’s Secret Sharing (SSS)

A method of splitting a secret into shares, where a defined threshold of shares reconstructs it. Note that reconstruction re-creates the full secret at one location — a meaningful difference from MPC.

Sharding

Partitioning a network so that different subsets of participants process different portions of the workload.

Shared Security

Arrangements in which multiple networks draw security from a common pool of staked capital.

Shared Sequencing

A sequencer set serving multiple rollups, enabling atomic cross-rollup operations and reducing fragmentation.

Sharpe Ratio

Risk-adjusted return, measured as excess return per unit of volatility.

Shielded Transaction

A transaction executed within a privacy pool, hiding sender, recipient, and amount.

Shill

To promote an asset one holds, typically without disclosure.

Short

A position that profits when the price falls.

Sidechain

An independent chain with its own consensus and security model, connected to a main chain by a bridge. A sidechain does not inherit the main chain's security — an important distinction from a rollup.

Signer

A key authorized to approve transactions within a multisig or governance structure.

SIM Swap

Fraudulently transferring a victim's phone number to intercept SMS-based authentication codes.

Simulation

Previewing a transaction's effects before signing, so the user sees the actual balance changes rather than raw call data.

Slashing

The confiscation of a portion of a validator's stake as a penalty for provably malicious behaviour, typically double-signing or contradictory attestations.

Slippage

The difference between the expected execution price and the price actually received.

Slippage Tolerance

The maximum adverse price movement a user will accept before a transaction reverts. Setting it too high exposes users to sandwich attacks.

Slot

A fixed time interval in which one block may be proposed. Twelve seconds on Ethereum.

Smart Contract

Program code deployed to a blockchain that executes deterministically according to its logic when invoked.

Smart Contract Vulnerability

A flaw in contract logic permitting unintended behaviour.

Smart Contract Wallet

A wallet implemented as an on-chain program rather than a simple key pair, enabling programmable rules such as spending limits, multi-approver flows, and recovery.

Snapshot Voting

Gas-free off-chain voting weighted by token balances recorded at a specified block.

Social Engineering

Manipulating people rather than systems to obtain access.

Social Recovery

A recovery mechanism where a set of designated guardians can collectively restore access to an account.

SocialFi

Social applications where identity, content, and audience relationships are represented as on-chain assets.

Soft Fork

A backward-compatible protocol change that tightens the rules. Non-upgraded nodes still accept blocks produced under the new rules.

Soft Rug

Gradual abandonment accompanied by insider selling, without a single identifiable theft event.

Software Wallet

A wallet application running on a desktop, mobile device, or browser.

Solidity

The dominant high-level language for writing EVM smart contracts.

Solver

A party that competes to fulfil user intents at the best available terms, absorbing execution complexity and risk.

Soulbound Token (SBT)

A non-transferable token representing credentials, affiliations, or reputation.

Spear Phishing

Phishing tailored to a specific individual using researched personal or organizational detail. The most common initial vector in large-scale organizational compromises.

Spot Trading

Buying or selling an asset for immediate settlement at the current price.

Spread

The difference between best bid and best ask. A primary indicator of liquidity and execution cost.

Stability Fee

The interest charged on a CDP.

Stablecoin

A token designed to maintain a stable value relative to a reference asset, most commonly the US dollar.

Stablecoin Rails

The use of stablecoins as settlement infrastructure for payments, remittances, and treasury operations.

Staking

Locking tokens to secure a network or to earn protocol rewards. Note that the term is used loosely across the industry: protocol-level staking, DeFi deposit programs, and marketing "staking" products carry very different risk profiles and should be distinguished carefully in any customer-facing material.

Staking Ratio

The proportion of total token supply actively staked, a key input to network security and to yield calculations.

State

The complete current set of data a blockchain tracks: account balances, contract storage, and related records.

State Channel

A construct where two or more parties transact off-chain by exchanging signed state updates, settling on-chain only at open and close.

State Transition

The change from one state to the next, produced by executing the transactions in a block.

Stealth Address

A one-time address derived for each payment so that transfers to the same recipient are not publicly linkable.

Stop-Limit Order

A stop order that, once triggered, places a limit order rather than a market order.

Stop-Loss Order

An order triggered when price reaches a defined level, used to cap losses.

Strategic Round

A round allocated to partners contributing distribution, liquidity, or technical support beyond capital.

Strike Price

The price at which an option may be exercised.

Stuck Transaction

A pending transaction with a fee too low for inclusion under current conditions, blocking subsequent transactions from the same account due to nonce ordering.

Sub-Account

A partitioned account within a master relationship, used for strategy isolation and internal reporting.

Sub-DAO / Working Group

A delegated unit with a defined mandate and budget.

Subgraph

A defined indexing specification describing which on-chain data to collect and how to expose it via an API.

Supply Chain Attack

Compromising a dependency, build pipeline, or third-party library to reach downstream targets.

Support

A price level where buying interest has historically halted declines.

Suspicious Activity Report (SAR) / Suspicious Transaction Report (STR)

The mandatory filing submitted to a financial intelligence unit when suspicious activity is identified.

Swap

An exchange of one token for another.

Sweep

Purchasing multiple listings at or near the floor in a single action.

Sybil Attack

Creating many pseudonymous identities to gain disproportionate influence.

Sybil Filtering

Analysis identifying and excluding addresses controlled by a single actor attempting to multiply an allocation.

Sybil Resistance

A system's defence against a single actor creating many identities to gain disproportionate influence. Proof of work and proof of stake are both fundamentally Sybil resistance mechanisms.

Synthetic Asset

A token whose value tracks an external reference asset without conveying ownership of it.