> For the complete documentation index, see [llms.txt](https://docs.x721.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.x721.io/guides/faqs/glossary.md).

# Glossary

**APR:** Annual Percentage Return.

**Collection:** A set of NFTs within the same contract.

**Collection Offer:** An offer which gets submitted on all items within a collection.

**Contract:** An U2U smart contract

**Floor Price:** The lowest amount of money required to spend to obtain an NFT using the *Buy Now* function.

**Gas:** The cost required to perform a transaction, priced in U2U.

**Launchpad:** Igniting the Future of Digital Collectibles.

**Royalties:** Fees which are paid to collection owners upon each trade done on X721 Marketplace.