What does IFR stand for in aviation?

IFR in aviation stands for Instrument Flight Rules. This term refers to a set of regulations under which a pilot operates an aircraft in weather conditions generally worse than the minimums specified for visual flight rules (VFR). Under IFR, pilots rely primarily on instruments for navigation and control of the aircraft, rather than visual references outside the cockpit. This allows for safe operation in a wider range of weather conditions and is essential for flying in clouds, fog, or at night.

The other options do not accurately describe the specific regulatory framework that governs instrument flying in aviation, making Instrument Flight Rules the correct and most relevant term for this context.