Satoshi (SATS)

The smallest unit of bitcoin with a value of 0.00000001 BTC.

Satoshi Nakamoto

The individual or group of individuals that created Bitcoin. The identity of Satoshi Nakamoto has never been confirmed.

Scam

A fraudulent or deceptive cryptocurrency or ICO.

Scrypt

An alternative Proof-of Work (PoW) algorithm to SHA-256, used in Bitcoin mining. Scrypt mining relies more heavily on memory than on pure CPU power, aiming to reduce the advantage that ASICs have and hence increasing network participation and energy efficiency.

Second-Layer Solutions

A set of solutions built on top of a public blockchain to extend its scalability and efficiency, especially for micro-transactions or actions. Examples include: Plasma, TrueBit, Lightning Network, and more.

Securities and Exchange Commission (SEC)

An independent agency of the United States federal government, responsible for enforcing federal securities laws, proposing securities rules, and regulating the securities industry, the nation's stock and options exchanges, and other related activities and organizations.

Seed Phrase

Seed phrase is a single starting point when deriving keys for a deterministic wallet. It is usually presented as a series of words to enable the owner to quickly backup or restore a wallet.

Segregated Witness (SegWit)

A Bitcoin Improvement Proposal (BIP) that aimed to fix transaction malleability on Bitcoin. In the past, when changing the “witness” information (signatures) on blocks, it would change the transaction ID and its subsequent hash; SegWit was aiming to fix this by segregating signature and block content; a side effect of this change was smaller block sizes and the ability to support second layer solutions.

Selfish Mining

A situation in which a miner mines a new block but does not broadcast this new block to the other miners. If this miner is able to find a second block faster than all other miners, then they would have created the longest public chain, invalidating all other blocks discovered in the time it took to execute this attack.

Sell Wall

A situation where a large limit order has been placed to sell when a cryptocurrency reaches a certain value. This can sometimes be used by traders to create a certain impression in the market, preventing a cryptocurrency from rising above that value, as supply will likely outstrip demand when the order is executed.

SHA-256

A cryptographic hash function that generates a 256-bit signature for a text, used in Bitcoin Proof-of-Work (PoW). Standing for “Secure Hash Algorithm”, it is one of the SHA-2 algorithms, first designed by the NSA.

Sharding

Sharding is a scaling approach that enables splitting of blockchain states into partitions containing states and transaction history so that each shard can be processed in parallel.

Shilling

The act of enthusiastically promoting a cryptocurrency or ICO project.

Shitcoin

A coin with no obvious potential value or usage.

Short

A trading technique in which a trader borrows an asset in order to sell it, with the expectation that the price will continue to decline. In the event that the price does decline, the short seller will then buy the asset at this lower price in order to return it to the lender of the asset, making the difference in profit.

Side Chain

A blockchain ledger that runs in parallel to a primary blockchain, where there is a two-way link between the primary chain and sidechain. This allows the sidechain to operate independently of the primary blockchain, using their own protocols or ledger mechanisms.

Silk Road

An online black market that existed on the dark web, now shut down by the FBI. It had accepted bitcoins for transactions.

Simplified Payment Verification (SPV)

A lightweight client to verify blockchain transactions, downloading only block headers and requesting proof of inclusion to the blockchain in the Merkle Tree.

Smart contract

A smart contract is a computer protocol intended to facilitate, verify, or enforce a contract on the blockchain without third parties.

Soft Cap

The minimum amount that an initial coin offering (ICO) wants to raise. Sometimes, if the ICO is unable to raise the soft cap amount, it may be called off entirely.

Soft Fork (Blockchain)

A protocol upgrade where only previously valid transactions are made invalid, with most soft forks requiring miners to upgrade their mining software in order to enforce it. 

Solidity

The programming language used by Ethereum for developing smart contracts.

Spot

A contract or transaction buying or selling a cryptocurrency for immediate settlement, or payment and delivery, of the cryptocurrency on the market.

Spot Market

A public market in which cryptocurrencies are traded for immediate settlement. It contrasts with a futures market, in which settlement is due at a later date.

Stablecoin

A cryptocurrency with extremely low volatility, sometimes used as a means of portfolio diversification. Examples include gold-backed cryptocurrency or fiat-pegged cryptocurrency.

Staking

Participation in a Proof-of-Stake (PoS) system to put your tokens in to serve as a validator to the blockchain and receive rewards.

Stale Block

A block which was successfully mined but not included on the current longest blockchain, usually because another block at the same height was added to the chain first.

State Channel

A second-layer scaling solution that reduces the total on-chain transactions necessary, moving the transactions off-chain and letting participants sign to the main chain after multiple off-chain transactions.

Symbol

The ticker of a cryptocurrency; for example, Bitcoin’s symbol is BTC.