Is it a rally or a 'dead cat bounce'?

What is a 'dead cat bounce?'   

The term "dead cat bounce" is used by technical analysts to explain a small, brief recovery in the price of a declining stock or the broader market, which is then followed by the continuation of a downtrend.

Derived from the idea that even a dead cat will bounce if it falls from a great height, the phrase is often used in hindsight although it is a good opportunity to initiate a short position.