FRANKFURT — The European economy shrank for a second quarter in a row, according to official data released Thursday, fulfilling a common definition of recession and signaling that the region still faces a long road to recovery.

Gross domestic product in the eurozone fell 0.1 percent in the three months through September compared to the previous quarter, according to Eurostat, the European Union statistics agency. The eurozone economy improved slightly from the second quarter, when it contracted by 0.2 percent. But it was the fourth quarter in a row of zero growth or worse.