TCV captures the full dollar value of a contract, typically the ACV multiplied by the contract length, plus any one-time fees (implementation, services, hardware) and any committed step-ups for years two and three. TCV is what gets reported when a 'big deal' is announced.
TCV is useful for comparing deal sizes but misleading for revenue forecasting. ARR, ACV, and recognized revenue all measure different things and should be reported alongside, not in place of, TCV.