EV/EBITDA stands for Enterprise Value to Earnings before Interest, Taxes, Depreciation and Amortisation (and Exceptionals). It is similar to - and often used in conjunction with - the PE Ratio but it is capital structure-neutral by including debt and taking earnings before the payment of interest.
It is calculated on a TTM basis.
EV/EBITDA is similar to - and often used in conjunction with - the PE Ratio to value a company but is arguably a better ratio for comparable multiples analysis. This is because EV is capital structure-neutral in that it includes debt.
Furthermore, EBITDA measures cash earnings without accrual accounting, cancelling tax-jurisdiction effects, and cancelling the effects of different capital structures. It is purely driven by the business operations of the company whereas the PE multiple can be impacted by non-business factors of a discretionary or non-recurring nature.