64-QAM, or 64-Quadrature Amplitude Modulation, is a digital modulation technique used to transmit data over radio waves. It combines both amplitude and phase variations to encode information, allowing for the transmission of six bits per symbol. This means that 64 different signal combinations can represent different data values, making it efficient for high-speed data communication. This method is commonly used in various communication systems, including Wi-Fi, cable modems, and digital television. By increasing the number of symbols, 64-QAM can achieve higher data rates compared to simpler modulation schemes, but it also requires a better signal-to-noise ratio to maintain reliability.