The two consecutive quarters of falling real gdp definition is a useful shorthand often called a technical recession, but it is not the official test anywhere. It can trigger when nothing much is wrong and fail to trigger when a genuine contraction is under way.
The committee that actually dates US recessions weighs depth, diffusion and duration across several monthly series, of which real personal income less transfers and non-farm employment carry the most weight. For traders the practical point is that recessions are declared long after they begin.
Example: real GDP falls 0.6% then 0.1% annualised in consecutive quarters while payrolls add 350,000 jobs a month. The technical definition says recession; the labour data says otherwise, and no recession was declared.
Related: nber-dating, business-cycle, soft-landing, leading-indicator, initial-jobless-claims