The Short-Time Fourier Transform (STFT) is a mathematical technique used to analyze signals that change over time. It breaks a signal into smaller segments, applying the Fourier Transform to each segment. This allows for the examination of both the frequency content and how it evolves, making it useful in various fields like audio processing and speech analysis. STFT provides a time-frequency representation of a signal, displaying how its frequency components vary with time. This is particularly helpful in applications such as music analysis, speech recognition, and vibration analysis, where understanding the dynamics of a signal is crucial for interpretation and processing.