Sat

Short for satoshi, the smallest unit of a bitcoin. Each sat is uniquely identified and numbered. There are 100 million sats in 1 bitcoin. Sats are just bitcoin, so people own sats just as they own bitcoin.

Inscription

Content recorded immutably on the Bitcoin blockchain. Folks might think of this as an “NFT”, but there’s much more to it, so read on!

Ordinal theory

Assigning unique serial numbers to sats, starting at 0 (for the first sat of the first bitcoin mined). Allows sats to be tracked on the Bitcoin blockchain across transactions.

Ordinals (protocol)

A protocol that uses Ordinal theory, and enables inscriptions that are paired with a sat. The combo of the Inscription and the Sat is the closest to a “Bitcoin NFT” but there’s more!

Inscription Number

Each inscription is numbered uniquely, starting at 0. In April 2024, we have reached inscription number 67,000,000. There is also a set of negative inscription numbers (see “cursed inscriptions”) that are numbered from -1 to -472,043. Future inscription numbers will all be positive and greater than 67,000,000, ie 67,000,001, 67,000,002, 67,000,003, and so on.

Reinscription

Each inscription is paired with a single sat, but each sat can have multiple inscriptions! Reinscription is the act of inscribing a sat two or more times. You can think of a sat as having multiple canvases and reinscription allows you to use additional canvases for that sat. When you transfer an inscription, you transfer the sat, so when you transfer a reinscription, you transfer all reinscriptions on that sat. You can think of these inscriptions on the same sat as a group of “soul-bound” NFTs that are forever bound together.

Parent-Child Provenance/Collections

This is the standard for creating a collection of inscriptions in Ordinals. Collections are one of the most important concepts in Ordinals! Parent-Child allows inscriptions to form a family tree that is immutably recorded on Bitcoin. Parent inscriptions can have Child inscriptions, and all the children form a collection on Bitcoin with clear provenance. If you’re familiar with Ethereum NFTs, this is kind of like the ERC-721 standard for NFT collections. The Bitcoin blockchain does not have smart contracts, so Parent-Child is the standard for an Ordinal collection. Parent-Child is more powerful than it first seems. Children can be Parents too, and you can have multi-generational family trees of grandchildren, and great-grandchildren on Bitcoin. Multiple parents can together create a single Multi-Parent-Child collection! Thinking about Parent-Child Provenance can make your mind explode with possibilities for the future!

Recursive Inscriptions

Inscriptions can refer to and use other inscriptions in their inscription. This is one of the most powerful features of Ordinals. Recursive Inscriptions enable composable and modular building with Ordinals. Every inscription is a building block that can be used in the future. For example, many generative art works use of libraries such as p5.js and three.js, and recursive inscriptions allow for the use of these libraries. Most generative art on Bitcoin uses recursive inscriptions.

Cursed inscriptions

A set of inscriptions from the early days of Ordinals that were not recognized by the developing Ordinals protocol. Cursed inscriptions are valid inscriptions that implemented features that were later added to Ordinals (such as Reinscription and Parent-Child Provenance). Cursed inscriptions were officially recognized at the Jubilee (a major update to Ordinals where the definition of an inscription was finalized in January 2024) and assigned negative inscription numbers from -1 to -472,043. There are unlikely to be any more cursed inscriptions in the future, so cursed inscriptions are a rare group of inscriptions (that can be identified with a negative inscription number).

Satributes

Definitions of special sats. Casey defined certain special sats in Rodarmor Rarity. For example the uncommon sat is the first sat in a bitcoin block. An example would be sat 45000000000, the first sat in block 9. Other special sats in Rodarmor rarity are: rare (the first sat of each difficulty adjustment period), epic (the first sat of each halving epoch), legendary (the first sat of each cycle), and mythic (the first sat of the genesis block). Other satributes include: Block 9 (sats from block 9, numbered 45000000000-49999999999). 450x (the first bitcoin in block 9, numbered 45000000000-45099999999). Palindrome (sat numbers that are palindromes). Others such as Vintage, Nakamoto, First Transaction, Pizza.