Looking for Definition of "VCOM" for ePaper Displays

While I'm waiting for my Good display GDEW027W3-2 to arrive I've been looking at their sample program and the display specification. There are a number of terms I wish there was a glossary for but the one that I simply cannot find the meaning of is "VCOM" I suspect it has to do with a voltage needed to flip or set the black or white particles.

Thanks
John

Abstract: The Vcom, common electrode , in thin film transistor-liquid crystal display (TFT-LCD) panels provides the reference DC voltage with TFT-LCD panel and functions as the path of current. The voltage of the distributed capacitive and resistive Vcom fluctuates according to changes of gate and data voltage.

first result of search "vcom dc meaning" on google.

Thank you :slight_smile:
I searched "epaper VCOM definition" and variations with no luck on a physical description.