A router's Service Set Identifier is a label that a router's administrator gives to the wireless network that the router broadcasts. The SSID for a nearby router can typically be found in the list of Wi-Fi networks that show up in the device's network or Internet connection settings.
Users often need to know the password associated with an SSID to connect to the router's wireless network. If a network requires a password, an image of a lock typically appears next to that network's SSID. A router's administrator can also hide the SSID for increased security. A Wi-Fi network that has a hidden SSID can only be accessed by someone who already knows the SSID and enters it manually into his Internet connection settings.
Locations such as coffee shops that have free Wi-Fi access often post the SSID and the associated password in signs in prominent locations so customers can find them easily. An SSID can be descriptive, so a coffee shop's SSID might be "Coffee-Fi" or a similar label that connotes a coffee theme. Once a user has connected to a network, he sees the word "Connected" next to the SSID; this can be useful in areas with many available networks.