Term

Leverage

Borrowed money an investor uses to increase the size of positions. Leverage magnifies both possible profits and losses.

Explained in

Fortune's Formula: The Untold Story of the Scientific Betting System That Beat the Casinos and Wall Street, William Poundstone
When Genius Failed: The Rise and Fall of Long-Term Capital Management, Roger Lowenstein
Using borrowed money to make a bet bigger. However many times the bet grows, the possible profit and the possible loss grow by the same factor.
High Output Management, Andrew Grove
For Grove: a measure of how much one action of a manager changes the team's output. Training has high leverage, while meddling in someone else's work can have negative leverage.
The Art of the Deal, Donald Trump, Tony Schwartz
Here: power in a negotiation. In the book it means having something the other side wants, or cannot do without.