Off-Ledger Currency

A currency that is created (minted) outside of the specified blockchain ledger but is accepted or used.

Offline Storage

The act of storing cryptocurrencies in devices or systems not connected to the internet.

On-Ledger Currency

A currency that is both minted on the blockchain ledger and also used on the blockchain ledger, such as bitcoin.

One Cancels The Other Order (OCO)

A situation where two orders for cryptocurrency are placed simultaneously, with a rule in place to enforce that if one is accepted, the other is cancelled.

Online Storage

The act of storing cryptocurrencies in devices or systems connected to the internet. Online storage offers more convenience but also increased risk of theft.

Open Source

Open-source software is a type of software released under a license in which the copyright holder grants users the rights to study, change, and distribute the software to anyone and for any purpose. It is also a philosophy, with participants believing in the free and open sharing of information in pursuit of the greater common good.

Open/Close

The price at which a cryptocurrency opens at a time period, for example at the start of the day; the price at which a cryptocurrency closes at a time period, for example at the end of the day. In general, these terms were more useful in traditional financial markets as there are fixed hours of the day in which trading occurs.

Option

A contract giving the buyer the right, but not the obligation, to buy or sell an underlying asset or instrument at a specified strike price. There are American and European options, the former of which may be exercised at any time before expiration, and the latter exercised only at the expiration date.

Options Market

A public market for options, giving the buyer an option to buy or sell a cryptocurrency at a specific strike price, on or before a specific date.

Oracles

An agent that finds and verifies information, bridging the real world and the blockchain by providing data to smart contracts for execution of said contracts under specified conditions.

Orphan

A valid block on the blockchain that is not part of the main chain. They may come into existence when two miners produce blocks at similar times, or caused by an attacker attempting to reverse transactions. This is sometimes also known as a “detached block”.

Over The Counter (OTC)

Over The Counter is defined as a transaction made outside of an exchange, often peer-to-peer through private trades. In jurisdictions where exchanges are disallowed or where amounts traded will move the markets, traders will go through the OTC route.

Overbought

When a cryptocurrency has been purchased by more and more investors over time, with its price increasing for an extended period of time. When this happens without any justifiable reason, the cryptocurrency is considered overbought, and a period of selling is expected.

Oversold

When a cryptocurrency has been sold by more and more investors over time, with its price decreasing for an extended period of time. When this happens without any justifiable reason, the cryptocurrency is considered oversold, and a period of buying is expected.