What does the Q signal “QRN” mean?

Q signals are a standard set of three-letter codes historically used in Morse code (CW) to save time, but they are also widely used in voice communications today. The Q signal "QRN" specifically refers to interference caused by natural sources, such as atmospheric static or lightning. A helpful way to remember this is that the "N" in QRN stands for "Nature" or "Natural" static. In contrast, another common Q signal, QRM, refers to human-made interference (where the "M" can stand for "Man-made").