Wavetable position

Wavetable position is the index into a wavetable's frames that selects which single-cycle waveform — or blend of adjacent waveforms — the oscillator is currently playing.

Position usually runs from the first frame to the last, and fractional values interpolate between neighbors so the sweep is continuous rather than stepped. Modulating position with an envelope or LFO is what turns a static table into evolving, vocal, or growling timbres, and the character of that motion depends heavily on how related adjacent frames are.