What does 10 delta mean?

In finance and options trading, 10 delta means an option with a delta of 0.10 or 10 percent, which has very specific implications. Delta measures how much an option's price is expected to move for a $1 move in the underlying stock. A 10 delta call option means if the stock moves up $1, the option price should increase by about $0.10. It also means the option has roughly a 10 percent probability of expiring in the money, making it a far out-of-the-money, low-probability trade. Ten delta options are very cheap, often costing only a few cents, and are used as lottery tickets for big moves or as hedges. For example, a trader might buy 10 delta puts as cheap insurance against a market crash. For puts, 10 delta would be expressed as -10 delta or -0.10, meaning it moves inversely to the stock. In other contexts, 10 delta could mean something else. In mathematics, it could simply mean a change of 10 units, as in Δ = 10. In chemistry, 10 delta has no standard meaning. But in trading, which is where the term 10 delta is most commonly used, it means a very low delta, far out-of-the-money option with low probability, low cost, and high leverage. Traders often refer to 10 delta, 25 delta, and 50 delta options to describe their risk profile.