Leverage
Borrowed buying power that lets you control a position larger than your own deposit.
Leverage is the ratio between the size of the position you control and the money you actually put up. If a broker offers 1:30 leverage, $1,000 of your own cash lets you trade a $30,000 position. The broker effectively fronts the difference for as long as the trade stays open.
The catch is that profit and loss are calculated on the full position size, not on your deposit. A 1% move on a $30,000 position is $300 - which is 30% of a $1,000 account. Leverage does not change the odds of a trade; it changes how fast the outcome hits your balance.
Regulators cap leverage precisely because of that speed. UK, EU and Australian retail accounts are limited to around 1:30 on major currency pairs, while offshore licences often advertise 1:500 or more. Beginners are usually better served by using far less leverage than the maximum on offer.