An SSID is the Name of a Network
The name of the network that you see when searching for wireless networks is an SSID.
Because multiple WLANs can coexist in one airspace, each WLAN needs a unique name—this name is the service set ID (SSID) of the network. Your wireless device can see the SSIDs for all available networks, therefore when you click a wireless icon, the SSIDs recognized by the device are listed. For example, suppose your wireless list consists of three SSIDs named MyWiFi2.4, MyWiFi5, and GuestWifi. This means that an administrator has created three WLAN Service profiles and, as part of each WLAN service profile, provided the SSID name for each. A single AP can support many SSIDs but its common practice to keep them to 3 or less.