Plain English Meaning
The way pilots fly along the low-altitude highways in the sky that connect VOR ground stations. You tune in the VOR, set the course shown on the chart, and follow the needle to stay on the line.
Full Definition
The methods used to fly along Victor airways, which are low-altitude federal airways defined by VOR ground stations and used between 1,200 feet AGL and 18,000 feet MSL. Pilots navigate these airways by tuning the appropriate VOR frequency, setting the published course on the navigation indicator, and tracking the radial to or from the station while remaining within the airway's (normally 4 either side of ).