Leverage
Margin, liquidation, how leverage affects profit and loss, funding.
Leverage lets you open a position larger than your own funds: with 10× leverage, $1,000 of margin opens a $10,000 position.
Leverage multiplies both profit and loss relative to the margin. A 5% move against a 10× position is −50% of the margin.
When the margin is not enough to maintain the position, the exchange closes it by force — that is liquidation.