STRIKE PRICE, EXPIRATION & MONEYNESS
Plain English
The strike price is the price you get to buy or sell the stock at. The expiration is the deadline. Moneyness tells you whether the option is 'winning' (in-the-money), 'losing' (out-of-the-money), or 'tied' (at-the-money) right now.
Going deeper
The strike price is the fixed price at which the option buyer can exercise the contract. The expiration date is the last day the option exists. Moneyness describes whether an option has intrinsic value. A call is In-The-Money (ITM) when the stock is above the strike, At-The-Money (ATM) when the stock equals the strike, and Out-of-The-Money (OTM) when the stock is below the strike. For puts, it's reversed. ITM options are more expensive but have a higher probability of profit. OTM options are cheaper but less likely to be profitable.
Examples
Moneyness Example
Stock ABC is at $100. The $95 Call is ITM (stock is above strike), the $100 Call is ATM, and the $105 Call is OTM (stock is below strike). The $95 Call costs $7.00, the $100 Call costs $3.00, and the $105 Call costs $1.00.
Expiration Impact
A $100 call expiring in 90 days might cost $5.00. The same $100 call expiring in 7 days might only cost $1.00 because there's much less time for the stock to move in your favor.