What does the 'V' in the mnemonic VDMONA stand for?

The 'V' in the mnemonic VDMONA stands for Variation between true and magnetic north. This concept is essential in aviation navigation because it refers to the difference in degrees between true north (geographic north) and magnetic north (the direction a magnetic compass points). Understanding this variation is crucial for pilots when planning and executing flight paths, as they need to convert true headings to magnetic headings or vice versa to navigate accurately. This ensures that pilots correct for any discrepancies caused by the Earth's magnetic field when using their compass or other navigational systems.