A secondary Wi-Fi hotspot created within a physical access point (AP).  One or more virtual access points (logical access points) can be created for different purposes.  For example, a virtual access point with one SSID could allow guest access to the Internet while another virtual AP with a different SSID could be set up for employees only.  This can also be used to assign a priority to different user groups by configuring the transmission speeds up or down in each virtual AP.  See 
VirtualWiFi and 
SSID.