$BCH refers to Bitcoin Cash, a cryptocurrency.
Short liquidation indicates that traders who had short positions (betting the price would decrease) are being forced to close their positions, often due to the price moving against them.
$1.009K likely refers to the liquidation value, which is $1,009 worth of BCH being liquidated.
$475.48 represents the price at which the liquidation occurred.
This could be part of a larger market trend where BCH's price rose and caused a cascade of short position liquidations. Liquidations happen when a trader's position reaches a certain threshold and they are forced to sell or buy to cover their position, often triggering further price movements.$BCH