Final answer:
VFR stands for Visual Flight Rules, which allow pilots to operate an aircraft under weather conditions clear enough to see where the aircraft is going with visual ground reference, in contrast to Instrument Flight Rules (IFR).
Step-by-step explanation:
In the field of aviation, the initials VFR stand for Visual Flight Rules. This is a set of regulations under which a pilot operates an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. Basically, it means the pilot must be able to operate the plane with visual reference to the ground, and by visual reference to other aircraft. VFR is the most common form of flight rules for small aircraft and is a part of pilot training and regulatory framework.
Pilots flying under VFR navigate using landmarks on the ground, avoid bad weather, and, most importantly, maintain a visual lookout for other aircraft to avoid collisions. In contrast to VFR, there is another set of rules known as Instrument Flight Rules (IFR), where pilots fly using instruments and navigation aids because outside visibility is too poor to fly by visual references.