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Guidebook — Glossary

Guidebook — Glossary

Your options vocabulary, explained plainly

30 terms to explore

No finance-speak. No textbook definitions. If you've ever felt talked down to by a brokerage explainer, start here. Every term is written for someone who's never traded options before — and never will apologize for that.

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1
Call
Term 1 of 30
A call option gives you the right to <em>buy</em> a stock at the strike price before expiration. You are not obligated to buy — you just have the option. Think of it as putting down a deposit on a house: you pay a small premium now for the right to buy at a set price later.
◆ Why it matters

Calls are how you bet that a stock will go up.

2
Put
Term 2 of 30
A put option gives you the right to <em>sell</em> a stock at the strike price before expiration. If you think a stock will drop, you buy a put to lock in a selling price.
◆ Why it matters

Puts are how you profit from falling stocks or protect existing holdings.

3
Strike price
Term 3 of 30
The strike price is the price at which you can buy (for a call) or sell (for a put) the underlying stock. If you buy a call with a $100 strike and the stock climbs to $115, you can still buy at $100.
◆ Why it matters

The relationship between strike price and current stock price determines whether an option is in, at, or out of the money.

4
Expiration date
Term 4 of 30
The expiration date is the last day an option contract is valid. After that date, the option ceases to exist — it either expires worthless or gets automatically exercised. Most retail options expire on Fridays.
◆ Why it matters

Time is your enemy in options. The closer you get to expiration, the faster your option loses value.

5
Premium
Term 5 of 30
The premium is the price you pay to buy an option — the upfront cost. It is quoted per share, and contracts cover 100 shares, so a $2.00 premium costs $200 total.
◆ Why it matters

Your premium is your maximum possible loss on a long option trade.

6
In the money (ITM)
Term 6 of 30
An option is in the money when exercising it would be profitable right now. A call is ITM when the stock price is above the strike price. A put is ITM when the stock is below the strike.
◆ Why it matters

ITM options have intrinsic value and cost more — they are more likely to expire profitably but come with higher premiums.

7
Out of the money (OTM)
Term 7 of 30
An option is out of the money when exercising it would not be profitable right now. A call is OTM when the stock is below the strike; a put is OTM when the stock is above the strike.
◆ Why it matters

OTM options are cheaper but require the stock to move in your direction to become profitable.

8
At the money (ATM)
Term 8 of 30
An option is at the money when the stock price is very close to the strike price. ATM options are equally balanced — the stock could just as easily go up or down.
◆ Why it matters

ATM options have the most time value and are often used when selling covered calls or straddles.

9
Intrinsic value
Term 9 of 30
Intrinsic value is the amount an option would be worth if you exercised it right now. A $105 call on a $110 stock has $5 of intrinsic value. If an option has no intrinsic value, it is purely time value.
◆ Why it matters

You never pay for intrinsic value — you either have it or you do not.

10
Extrinsic value (time value)
Term 10 of 30
Extrinsic value is the portion of an option price that reflects the chance it will become more profitable before expiration. It is highest when there is more time and more uncertainty.
◆ Why it matters

Time value decays as expiration approaches — the more you pay for time value, the more you are betting on movement.

11
Time decay (theta)
Term 11 of 30
Theta is the rate at which an option loses value each day due to time passing. The closer you are to expiration, the faster theta eats into your position.
◆ Why it matters

Time decay is the silent killer of long option positions. A stock that barely moves can leave you with a worthless option.

12
Implied volatility (IV)
Term 12 of 30
Implied volatility is the market expectation of how much a stock will move. When IV is high, option premiums are expensive. When IV is low, they are cheap. It is calculated from actual option prices, not historical data.
◆ Why it matters

Buying options when IV is high is like paying full price — you are paying for a lot of optimism that may not materialize.

13
Delta
Term 13 of 30
Delta measures how much an option price moves for every $1 move in the underlying stock. A delta of 0.50 means the option moves $0.50 for every $1 in the stock.
◆ Why it matters

Delta tells you how your option behaves like the stock. High delta = more stock-like. Low delta = more lottery-ticket-like.

14
Gamma
Term 14 of 30
Gamma measures how fast delta changes when the stock moves. It is highest for at-the-money options close to expiration.
◆ Why it matters

Gamma is why short-dated options can swing violently — small moves in the stock cause big swings in delta, which amplifies the price change.

15
Vega
Term 15 of 30
Vega measures how much an option price changes for every 1% change in implied volatility. High vega means the option is sensitive to IV swings.
◆ Why it matters

If you buy options before an earnings report (when IV spikes) and the stock barely moves after, vega crush will eat your position even if the direction was right.

16
Rho
Term 16 of 30
Rho measures how much an option price changes for every 1% change in interest rates. For most retail traders, rho has minimal practical impact.
◆ Why it matters

In low-interest-rate environments, rho is barely worth tracking. In high-rate environments, it can meaningfully affect deep-in-the-money options.

17
Open interest
Term 17 of 30
Open interest is the total number of option contracts that are currently open (held by traders, not yet closed or exercised). It shows how much interest exists in a particular strike and expiration.
◆ Why it matters

High open interest means easier entry and exit — you are more likely to get a fair price when trading.

18
Volume
Term 18 of 30
Volume is the number of contracts traded in a given period. Unlike open interest, volume resets daily. High volume means lots of recent trading activity.
◆ Why it matters

Volume confirms whether a price move is real or just noise. Low volume = thin market = wider spreads.

19
Bid
Term 19 of 30
The bid is the highest price a buyer is currently willing to pay for an option. When you sell an option, you sell at the bid.
◆ Why it matters

The bid is always lower than what you would pay to buy the same option. That gap is the market maker profit.

20
Ask
Term 20 of 30
The ask (also called offer) is the lowest price a seller is currently willing to accept for an option. When you buy an option, you buy at the ask.
◆ Why it matters

Always check the bid-ask spread before trading. Wide spreads mean you are giving up significant value just to get in.

21
Spread (bid-ask spread)
Term 21 of 30
The spread is the difference between the bid and the ask. A narrow spread means a liquid, efficient market. A wide spread means you are paying a premium to the market maker just to participate.
◆ Why it matters

Tight spreads save you money on entry and exit. Stick to options with spreads of $0.05–$0.10 or less.

22
Exercise
Term 22 of 30
To exercise an option means to use your right to buy (call) or sell (put) at the strike price. Most traders never exercise — they sell the option instead because it is usually more profitable and requires less capital.
◆ Why it matters

Exercising converts your option to an actual stock position. Know what you are getting into before you do it.

23
Assignment
Term 23 of 30
Assignment happens when the person on the other side of your option exercises their right, forcing you to fulfill the contract. If you sold a call and you are assigned, you must sell the stock at the strike price.
◆ Why it matters

Assignment risk is why you never sell naked options — always have the capital or shares to back it up.

24
Contract (100 shares)
Term 24 of 30
A single option contract covers 100 shares of the underlying stock. When people say "per contract," they mean per 100 shares.
◆ Why it matters

An option priced at $3 actually costs $300 (3 × 100 shares). Always multiply the premium by 100 when calculating your actual cost.

25
Break-even price
Term 25 of 30
Your break-even price is the stock price at which your trade neither makes nor loses money. For a long call, it is the strike price plus the premium paid. For a long put, it is the strike price minus the premium paid.
◆ Why it matters

Knowing your break-even tells you exactly what the stock needs to do for you to start profiting.

26
Covered call
Term 26 of 30
A covered call means you own 100 shares of the underlying stock and sell a call option against those shares. The call is "covered" because you can deliver the shares if assigned.
◆ Why it matters

Covered calls generate income on stocks you already own. They are a common income strategy, not a direction bet.

27
Cash-secured put
Term 27 of 30
A cash-secured put means you sell a put option while setting aside enough cash to buy the stock at the strike price if assigned. The "cash-secured" part means you have the money to back the obligation.
◆ Why it matters

Selling cash-secured puts is a way to buy a stock you want at a discount — you collect premium and might get assigned at a price you like.

28
Long call
Term 28 of 30
A long call is simply buying a call option — going long on a call. You pay a premium for the right to buy at the strike. Your max loss is the premium; your profit potential is unlimited.
◆ Why it matters

A long call is the most direct way to bet that a stock goes up with limited downside.

29
Long put
Term 29 of 30
A long put is simply buying a put option — going long on a put. You pay a premium for the right to sell at the strike. Your max loss is the premium; your profit is capped at the strike price (minus premium).
◆ Why it matters

A long put is how you profit from a stock falling or hedge existing positions against a downturn.

30
Max loss
Term 30 of 30
Your maximum loss on a long option position is the premium you paid — nothing more. You cannot lose more than you put in. This is one of the key advantages of buying options over other derivatives.
◆ Why it matters

Knowing your max loss before entering a trade means you can size your position so a total loss does not hurt you.

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