According to the Bureau of
At the worst point, real GDP was off 5.1% from the 2007 peak. Since the most common definition of a depression is a 10%+ decline in real GDP, the 2007 recession was not a depression. Note: There is no formal definition of a depression. Some people use other definitions such as the duration below the previous peak. By that definition, using both GDP and employment, this seems like the "Lesser depression", but not by the common definition.