An SSID is a technical term for the network name of the Wi-Fi Network. It may be the name of Wireless Network from a wireless router or from a hotspot. SSIDs are meant to be unique names so that different Wi-Fi networks in an area can be distinguished from each other and people can connect to the correct one. For instance, at public places, you will find different wireless networks, each with a different SSID, representing different wireless networks.
The SSID is case-sensitive and can as long as 32 characters. It may contain alphabets, numbers, and special characters and it can say anything if it is under the 32 characters limit. By default, most of the routers have a default SSID that is set by the manufacturers and is either the name of the manufacturer or the model of the router.
Your mobile phones and laptop connect to the Wi-Fi Network through the SSIDs because the wireless routers broadcast their signals through these SSIDs and hence the wireless networks become visible to other devices. If a wireless network has encryption enabled then a lock will appear next to the SSID indicating that this network is password protected.
If someone doesn’t want to broadcast his wireless network publicly then most of the wireless routers have the option available to disable SSID broadcasting to enhance the security of their wireless router. If SSID broadcasting is disabled then the security of the router is enhanced because the people who want to connect to the network have to know two things; the exact SSID of the network and its password. If you want to connect to a network with SSID broadcasting disabled then you will have to manually create a profile for the network with its exact SSID and other connection parameters.