The SSID (Service set identification) is the name of your wireless network, e.g. "TomTees_WLAN". You can disable the broadcasting of the SSID, so that it's not that obvious for everyone that there is such a network available, but that's not a real protection, as it can still be detected.
I'm sure what hayabusa was referring to was more towards changing the default credentials and such. Also be sure to enable a strong encryption with a long passphrase (e.g. WPA2 Personal (PSK) + AES). I'd also recommend to disable
WPS, if supported by the device (I didn't check its specifications).