Short
Basics
What it means
Betting that an asset will fall in price. You borrow the asset, sell it now, and aim to buy it back cheaper later to return it.
Example
You short 50 shares of TSLA at $250. If it drops to $230, you buy back for $11,500 instead of the $12,500 you received, pocketing $1,000.
Mistake beginners make
Beginners forget the loss on a short has no fixed ceiling -- if TSLA runs to $500 you owe far more than you started with. Shorting is not just "long in reverse."