Floating-point operation (FLOP) - Any mathematical operation or assignment involving floating-point numbers; it is the metric used to measure cumulative training compute and fixes the AI Act's Art. 51(2) systemic-risk presumption at above 10²⁵ FLOP, a threshold the European Commission's GPAI Q&A estimates currently costs 'tens of millions of Euros' to reach (citing Epoch AI, 2024) (EU AI Act, Art. 3(67)).