> For the complete documentation index, see [llms.txt](https://docs.secured.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.secured.finance/fixed-rate-lending/core-concepts.md).

# Core Concepts

This section explains the mechanics of the protocol. If you read the pages in order, each builds on the last:

1. [**Zero-Coupon Bonds**](/fixed-rate-lending/core-concepts/zero-coupon-bonds.md) — the instrument everything is built on: how a discounted price becomes a fixed rate
2. [**Order Book & Order Types**](/fixed-rate-lending/core-concepts/order-book.md) — how lend and borrow orders meet, and when to use limit vs. market orders
3. [**Fixed Maturity & Auto-Roll**](/fixed-rate-lending/core-concepts/fixed-maturity-and-auto-roll.md) — quarterly markets, and what happens to positions at maturity
4. [**Collateral**](/fixed-rate-lending/core-concepts/collateral.md) — accepted assets per network, and how collateral secures loans
5. [**Liquidation**](/fixed-rate-lending/core-concepts/liquidation.md) — what happens when collateral coverage falls short
6. [**Tokenization**](/fixed-rate-lending/core-concepts/tokenization.md) — turning positions into transferable ERC-20 ZC Tokens
7. [**Fees**](/fixed-rate-lending/core-concepts/fees.md) — the complete fee structure

## Terminology used throughout

| Term                 | Meaning                                                                                  |
| -------------------- | ---------------------------------------------------------------------------------------- |
| **Lend / Buy**       | Buying a ZC bond at a discount — you are the lender                                      |
| **Borrow / Sell**    | Selling a ZC bond against collateral — you are the borrower                              |
| **Face value / Par** | 100 — the value every ZC bond reaches at maturity                                        |
| **Unwind**           | Closing a position by taking the opposite side in the same market                        |
| **Auto-Roll**        | The protocol-wide mechanism that rolls matured positions into the nearest 3-month market |
| **Itayose**          | The opening auction that sets a fair price when a new market starts                      |

All numeric parameters (fees, thresholds, limits) live in one place: [Protocol Parameters](/fixed-rate-lending/protocol-parameters.md).