Normally a waveform refers to a drawing of a sound.  But with Sound Sculptor waveforms will also refer to one cycle or period of a sound that's 512 samples long.  The built in waveforms are Pulse, Random, Saw, Sine, Square, and Triangle.  Any waveform or sound in the Waveforms folder will show up on the waveform popup menu for the Oscillator and LFO.  Waveforms must be 8 bit and mono.

You can also make your own waveforms and store them in the Waveforms folder (use "Pitch" to make one cycle 512 samples long so the frequency will be correct).  Don't use special characters in the name of the waveform or the program may act incorrectly.

To see a sample of a waveform, set the sample rate to 22kHz, select Oscillator from the Effects menu, set waveform to Sine, Frequency to 43.4648 Hz and Length to 512 samples.