📖 Glossary — the short words, in plain English

The site uses a few Greek letters and a lot of three-letter words. This is the one place that explains them all. If a page shows a word you do not know, it is here.

Option basics The option book Greeks & dealer exposure Volatility Statistics Chart indicators Words of this site

Option basics

Word	What it means
Call	A contract that gains when the price goes up past a chosen price.
Put	A contract that gains when the price goes down past a chosen price.
Strike	The chosen price written into the contract — "the 150 call".
Expiry	The last day the contract lives.
DTE	Days To Expiry. "30d" = 30 days left.
Spot	The price of the stock (or fund, or future) itself at the close.
ATM · OTM · ITM	At the money (strike next to spot) · out of the money (worth nothing if it ended today) · in the money (already worth something).
OI	Open interest: contracts people are holding overnight. The "stock" of positions. It is published once a day, so it lags one session.
Volume	Contracts that traded today. The "flow".
Premium	The price paid for an option. "Premium flow" is the money that changed hands.
Bid · Ask · Mid	What a buyer offers · what a seller asks · halfway. You rarely trade at the mid.
Credit · Debit	A trade that pays you when you open it · one that costs you.
Breakeven	The price at expiry where a trade neither makes nor loses money.
Session	One trading day.

The option book

"The book" is all the open contracts on one ticker, added up.

Word	What it means
Call wall	The strike above price with the most open call contracts, among the strikes within 25 % of the price. Often behaves like a ceiling.
Put wall	The strike below price with the most open put contracts, among the strikes within 25 % of the price. Often behaves like a floor.
Far hedge	A strike further than 25 % from the price that holds even more open interest than the wall — a long-dated position or a crash hedge. Shown for what it is, never drawn as a level: the price does not meet it. In the files it is `call_wall` / `put_wall` (every strike counted); the walls the pages draw are `call_wall_near` / `put_wall_near`.
Wall 2 · Wall 3	The next walls further from price.
Max pain	The expiry price at which option buyers would lose the most in total. Some traders think price drifts toward it near expiry.
γ flip (gamma flip)	The price where dealer gamma changes sign. Above it the book is usually calmer; below it moves tend to be bigger.
δ flip	The price where the book's net delta changes sign.
P/C ratio	Puts ÷ calls. 1.0 = equal, 2.0 = twice as many puts.
Turnover	Volume ÷ open interest. 0.10 = one contract in ten traded today.
Horizon · DTE bucket	The book cut by time: 0–14 days, 15–45, 46–180, 181+. Each is its own small book with its own walls.
Dealer	The market maker on the other side of most trades. Dealers hedge with the stock, and that hedging can push the price.

Greeks & dealer exposure

"Greeks" say how an option's value changes when something else changes. Added up over the whole book and turned into dollars, they become exposures.

Symbol	Name	Plain meaning
Δ	Delta (DEX for the book)	How much the option moves when the stock moves $1. Also a rough chance of finishing in the money — a 25Δ option ≈ 25 %.
Γ	Gamma (GEX)	How fast delta changes. Big gamma = dealers must trade a lot of stock when price moves. Positive: they sell rallies and buy dips (calmer). Negative: they chase the move (bigger moves).
Va	Vanna (VEX)	How delta changes when implied volatility changes. After an event, falling IV can force dealer buying or selling.
Ch	Charm (CHEX)	How delta changes as time passes. Near a big expiry the passing days can force dealer trades.
ν	Vega	What an option gains or loses when implied volatility moves one point.
θ	Theta	What an option loses each day just because time passes.
σ	Sigma	One "standard move". About 2 days in 3 stay inside ±1σ.

Volatility

Word	What it means
IV	Implied volatility: how big a move option prices expect, as a yearly %. It is a price, not a forecast — it says how big a move is paid for, never which way.
IV30 · IV60 …	IV for a contract a fixed 30 (60 …) days away, so the line does not jump when an expiry rolls off.
IV rank	Where today's IV sits between the lowest and highest of the past year. 0 = the lowest, 100 = the highest.
RV · realised vol	How much the price actually moved, in the same yearly units as IV.
Rich · Fair · Cheap	IV well above · near · below the realised vol. Rich options pay more to sell; cheap ones cost less to buy.
Expected move	The ±1σ move the options price in. Rule of thumb: price × IV × √(days ÷ 365).
Term structure · slope	IV across expiries. Rising to the right = contango (normal, calm). Falling = backwardation (near-term fear or an event).
25Δ skew	IV of the 25-delta put minus IV of the 25-delta call. Positive = protection costs more than upside (normal for stocks).
IV crush	The drop in IV right after an event such as earnings.

Statistics, in plain words

Word	What it means
z · z-score	How unusual today is for this ticker, against its own recent past. 0 = normal, +1 = high, +2 = very high, −1 = low, −2 = very low.
Percentile · "90th"	Today is higher than that share of past days. 90th = higher than 90 days out of 100.
Warming up	Not enough past days yet to say what is normal.
Base rate	How often something happens on any day. A reading only means something if it beats this.
ρ (rho)	A correlation: +1 move together, −1 move opposite, 0 no link.
Divergence	Price went one way and a line went the other. A description of that day, not a call.
R-multiple	A result measured in units of the trade's own risk — so trades of different size compare.

Chart indicators

Word	What it means
SMA · EMA	Average of the last N closes · the same, weighting recent days more. 20 / 50 / 200 are the usual lengths.
RSI	0–100 gauge of how one-sided the last 14 bars were. Above 70 = stretched up, below 30 = stretched down (a condition, not a signal).
CCI	How far price is from its own average, in units of its usual wobble. Beyond ±100 = stretched.
MACD	The gap between a fast and a slow average, and its own signal line. A cross of the two is a change of momentum.
Stochastic · Williams %R	Where the close sits inside the recent high–low range. Near the top = high in its range.
ADX · +DI · −DI	ADX is how strong a trend is (not which way): above 25 = a real trend. +DI / −DI say whether buyers or sellers lead.
ATR	The ticker's normal daily range, in dollars (or in % of price).
Bollinger %B · width	Where price sits inside its band (0 = lower edge, 1 = upper) · how wide the band is.
TTM squeeze	The Bollinger band is inside the Keltner channel: the range is unusually tight.
MFI	Like RSI but weighted by volume.
Support · Resistance	A price level where a fall (support) or a rise (resistance) has paused before.
Channel	Two parallel trend lines holding the price between them.

Words of this site

Word	What it means
The series	The 121 daily lines written for every ticker from its option chain — gamma, walls, IV, flow… One row per trading day.
Simple · Detailed	The switch at the top of a ticker page. Simple shows the headline and the main chart; Detailed opens everything.
.F	A futures contract: `CL.F` is crude oil, `CL` is the stock.
Own history	Every "unusual" on the site is measured against the same ticker's own past, never against other tickers.
Descriptive only	Nothing on the site is a forecast, a target or a recommendation: a number is a distance, a position or a count read off the data.