It means you can't use the keyboard unless you press a certain combination of buttons in order to unlock it. It's so the phone wouldn't accidentally dial someone while in your pocket.
It varies from brand to brand, but you usually pres or hold the * or # or 0, and a message appears on the screen.
Password lock
A land line is a house phone, that must be attached to a phone line or a device connected to a phone line. A cellular phone is a mobile phone that allows you to move freely anywhere.
In Case (of) Emergency
how do i lock my phone
The spelling is "cellular phone" which is normally shortened to "cell phone."
my spice phone is lock what i do
"My phone number is"
Cellular is an adjective; phone is a noun.
reset phone lock
phone lock
Cellular phone
1122,0000,1234