What is meant by default correlation?

What will be an ideal response?

For a portfolio of corporate bonds, there is the risk that some event that triggers the default of one of the corporate bonds in the portfolio will adversely impact another corporate bond in the portfolio, thereby increasing the probability of the default of that second corporation. A commonly used statistical concept to gauge the dependence between two variables is correlation. In credit risk management, this type of risk is referred to as default correlation. One would expect that for corporate issuers in the same industry sector, default correlation is high.