> For the complete documentation index, see [llms.txt](https://studybitcoin.gitbook.io/hndl-bitcoin-handle-naming-system/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://studybitcoin.gitbook.io/hndl-bitcoin-handle-naming-system/1.3-terminology.md).

# 1.3 Terminology

**Handle:** This term designates a unique non-fungible token (NFT) ERC-721, which serves as a personalized identifier appended with a .₿ suffix, also known as the Parent Handle. *For example: nakamoto.₿*

**Sub-Handle:** This term refers to a unique NFT ERC-721 associated with a parent handle, distinguished by a .₿ suffix. *For example: satoshi.nakamoto.₿*

**Expiration Timestamp:** This timestamp is determined using the block.timestamp for the handle. Subsequently, the timestamps are converted to human-readable dates using an appropriate converter. 

*Example: Timestamp: 1716958039 = Wednesday, May 29, 2024 12:47:19 AM GMT-04:00 DST*

**Token ID:** This represents the token number associated with the handle.

**Fee Recipient:** This designates the address responsible for collecting registration and renewal fees.

**Ownership Transfer:** This denotes the process of transferring ownership of handles from one user to another.

**Halving:** Registraion/Renewal fees are halved every 8 years until the 9th cycles then resets back to initial.

**Token Bound Account (TBA):** This concept, as outlined in the ERC6551 standard, attaches a smart contract account to every NFT. This enables it to own assets, execute transactions, and interact with decentralized applications (dApps).