Cover On A Bounce

What Does Cover On A Bounce Mean?
The covering of a short position after it has reached and bounced off a level of support. This strategy waits for the price to move to a support level, instead of selling before, to see if the level will hold  - because the trader will benefit if it doesn't hold. Once the security bounces, it is clear the security will have trouble moving down further, so the trade covers the short position.

Investopedia explains Cover On A Bounce
Levels of support act as a backstop to a further move downward in price, but can sometimes fail to hold. If a security falls below a support level, it will often lead to an even stronger downward move as the level is taken out. The trader waiting for a bounce is betting that the support level will not hold and they will benefit if this materializes.