FFT resynthesis
FFT resynthesis analyzes a waveform with a fast Fourier transform (the algorithm that reports one magnitude and phase per frequency slot), edits that spectrum, and rebuilds a waveform from it with the inverse transform.
In wavetable work the cycle is transformed into per-bin magnitudes and phases, edited at that level — combing out partials, shifting formants, resetting phase — and inverted into the frame that actually gets stored. It is the machinery behind spectral morphs and harmonic-editing views, and it gives control over a frame's spectrum that has no clean equivalent in the time domain.