Glossary
Every term these pages use with a precise meaning, defined once, with the rule that fixes it.
Spec v0.9.1, reviewed 2026-09-08
Terms are grouped by what they belong to. Where a word has a loose everyday sense and a precise one here, the precise one is the only one used.
| Term | Meaning |
|---|
| Stock token | An ERC-20 on Robinhood Chain issued by Robinhood's issuing entity, tracking the price of a listed share or fund. It is a certificate, not a share. The protocol holds it raw and never wraps it. |
| fyUSD | The stablecoin Fyber mints against a deposit. Eighteen decimals, no rebase, no transfer fee, no blocklist, no owner. Its whole supply equals the debt outstanding plus the USDG the peg module took in. |
| sfyUSD | The ERC-4626 wrapper over one branch's Stability Pool. One per branch. Its share price rises with the interest the pool receives. |
| USDG | The Paxos stablecoin the peg module swaps against. Six decimals, normalised on the way in. The only asset the peg module holds. |
| stLP | The share token of one equity/fyUSD vault. A claim in kind on the vault's holdings, not a stablecoin and not a pool share. |
| FBR | Fyber's token. Fixed supply of 100,000,000 FBR, minted once, distributed for using the protocol. It governs nothing in version 1. |
| sFBR | FBR staked, weighted by how long it has been staked. Not transferable. |
| Term | Meaning |
|---|
| Branch | One contract per collateral: positions, debt, constants, price adapter, Stability Pool, depth oracle and volatility oracle of its own. Twenty exist; nothing is pooled between them. |
| Dormant branch | A branch deployed at day 0 that cannot mint yet. It accepts pool deposits and opens itself when eight on-chain criteria are met (Rule R-12.3.2). |
| Position | One per address per branch: raw collateral, recorded debt, chosen rate, timestamps, redistribution snapshots. |
| Collateral ratio | collateral × price ÷ debt, for one position (ICR) or for a whole branch (TCR). |
| Loan-to-value | The inverse of the collateral ratio. 125% of ratio is 80% of loan-to-value. |
LTV_cap | The ceiling on the loan-to-value of a tier: 80%, 75%, 65%. It is a ceiling, never the figure of a given day. |
LTV_floor | The floor under the same figure: 60%, 50%, 40%. Borrowing never closes below it. |
ltvMax | The borrowing limit of the day, computed from realised volatility once per fixed 24 hours slot. It governs opening, borrowing more, and withdrawals that increase risk. A withdrawal that reduces risk is judged on LTV_cap instead (Rule R-19.16). |
MCR | The liquidation threshold: 115%, 122%, 140%. Fixed per tier, identical at every hour, and it reads neither the price confidence nor the volatility. |
CCR / SCR | The branch ratio under which minting freezes, and the one under which the branch can shut itself down. |
| Minimum debt | 1,000 fyUSD. A position holds that much or nothing, unless a redemption reduced it. |
| Term | Meaning |
|---|
| Anchor | The exchange feed of the branch, and the reference the composite is clamped around. Two are declared in order; the second takes over if the first stops publishing. |
| Family | What a source measures. F0 is the anchor, F1 the on-chain pools of Robinhood Chain, F2 signed indices and perpetuals, F3 twin tokens on another venue. |
| Signer group | Who signs a source. G_OBS is the on-chain observer and has no signer; G_WH is the Wormhole guardian set; G_REP is the five reporters; G_CL is the exchange feed. Two sources from one group are never independent. |
| Group cap | No signer group may carry more than 49% of the median. |
| Composite | The weighted median of the family values, clamped around the anchor. |
| Confidence | A number between zero and one, computed from the summed quality of the live sources and their dispersion. It never reads the clock. |
| Haircut | The discount applied to your collateral when the protocol trusts the price less: H_MAX × (1 − confidence), up to 12% on tier 1. It bites on borrowing and withdrawing only. |
| Dispersion | The widest relative gap between two family values. Above 1.5% the branch leaves the full regime; above 3% liquidations freeze. |
| Clamp | How far the composite may sit from the anchor: 25% on tier 1, and a narrower band when only two sources answer. |
| Reporter | One of 5 fixed keys that sign public quotes. 3 signatures make a bundle. They are witnesses: their group can never be the median on its own and can never produce the full regime. |
pRef / pLiq / pRedeem | The three prices, with three jobs: valuing a position, executing a liquidation, executing a redemption. They are never confused. |
| Term | Meaning |
|---|
| LIVE24 | At least 3 fresh sources across two families and two signer groups, one of them not a reporter, agreeing within 1.5%. Everything runs. |
| DEGRADED | Two sources of different groups, or three that disagree more than the full regime tolerates. Everything runs, with a haircut and a smaller liquidation bonus. |
| FROZEN | Too few independent sources, or they contradict each other, or the composite left its clamp. Liquidations stop and nothing else does. |
| HALT | No valid exchange price at all. Borrowing, withdrawing, liquidating and redeeming stop; repaying, adding collateral, closing and pool withdrawals do not. |
| Edge | 600 seconds after a price returns, during which the Stability Pool executes nothing. |
| Mint freeze | A branch below its CCR, or carrying bad debt, refuses new borrowing and withdrawals. Everything else is normal. |
| Term | Meaning |
|---|
| Flag | The first of two steps. A position under its threshold is flagged, then liquidatable after 90 seconds and for 1800 seconds. |
| Close factor | How much of a debt one liquidation takes: enough to bring the position back to 121% on tier 1, or the whole of it below 105%. |
| Bonus | The discount the buyer of the collateral keeps: 2% to 4% on tier 1, depending on confidence. |
| Bucket | An hourly ceiling on liquidated debt, expressed as a multiple of measured exit depth, so a rush cannot dump more than the market absorbs. |
| Stability Pool | The fyUSD reserve of one branch. It burns debt and receives the collateral. It starts empty, and a branch whose pool is empty has a debt ceiling of zero. |
| Bad debt | Supply with no debt behind it, after a liquidation that did not cover. Absorbed by a fyUSD reserve, then by seized stake, then spread across the branch's borrowers by index. |
| Solvency tolerance | The fall a position sitting exactly at its threshold survives before liquidating it stops covering the debt: 8.7%, 12.7%, 22.9%. |
| Term | Meaning |
|---|
d2 | The quantity of a token sellable on-chain before the average execution price moves 2% from mid. Measured hourly, and it only rises slowly. |
D_max | The debt ceiling of a branch: the smallest of four terms, one of which is its own Stability Pool divided by 0.4× on tier 1. Activating one branch never reduces another's. |
SP_CAP_FLOOR | $500,000: a floor under a pool's deposit cap, so a branch with no debt yet can still take money. Not a deposit anybody makes. |
PSM_BOOTSTRAP | 1,000,000 fyUSD: what the peg module may always have minted whatever the supply, so a first fyUSD can exist. |
C_abs | The dated step of that ceiling, from $200,000 across the protocol at day 0 up to $37,000,000 if all twenty branches reach their last step. |
| Ladder lock | Cumulative bad debt above 0.5% of the current cap stops a branch at the step it reached, for good. |
| Term | Meaning |
|---|
| Season | 90 days, counted from the first one, which opens 180 days after deployment. |
| Season counters | Non-transferable on-chain tallies of what an address did: fyUSD-days deposited, fyUSD of interest paid, in-range liquidity-time, and in-range vault value multiplied by its lock. They are converted into FBR by a fixed curve and are not a promise. |
| Staking weight | What a staked lot counts for: 25% on the day it is staked, rising to the whole of it after 365 days. |
| Exit line | What leaving costs, on a straight line between four points: 70% immediately, 50% after a day, 30% after three days, nothing after 7 days. Twelve hours costs 60%, two days 40%, five days 15%. Withdrawing part of a stake lowers the age of the rest by the fraction withdrawn rather than resetting it. |
| Boost | A staker's larger share of the same pool yield, up to 1.50×. It divides one flow; it creates none. |
| Shield | Up to 2% added to a borrower's place in the redemption queue, without changing the rate paid. |
| Backstop | The fyUSD reserve that absorbs bad debt first. It starts at zero, fills only from revenue, and reaches 2% of the debt somewhere between the end of the second year and the end of the third; nothing is paid to stakers before that. Anything above the target leaves at the next flush toward the buy-back, and the residue goes back to depositors 90 days after Sunset. |
| Term | Meaning |
|---|
| Vault | One per branch. It holds a two-sided Uniswap v4 position in a stock/fyUSD pool only the vaults may add liquidity to, and at most one single-asset position beside it. |
| Range | How far the vault buys down and sells up: 40% and 25% on tier 1, measured over five years of prices and frozen. |
| Recentring | Anyone may recentre a vault when the price has moved 15% from its centre and 24 hours have passed, and while its own pool is within 1% of the composite. It never swaps. |
| Lock step | 7 days to 365 days, carrying a counter multiplier up to 3.0×. |
| Term | Meaning |
|---|
| Closer | A 2-of-3 multisig of published team addresses. It can freeze for at most 72 hours, freeze liquidations for at most 24 hours, or close a branch for good. It expires 365 days after deployment and can never be extended. |
| Shutdown | A branch that stops lending for good. Urgent redemptions open the same day, or 7 days later when the Closer key ordered it, and what is left settles 30 days after that. |
| Sunset | The terminal mode of the whole protocol, triggered by 3 shut branches or an aggregate ratio under 110%. |