What does it mean to unlock a cellphone?

Question

I've heard this term used in a review for a cell phone: -This phone is not easily unlocked (I actually failed, so I am stuck, but I like my service so this isn't a biggie)

I don't know what they're talking about... anyone?

Answer 1

You give the phone a code so that you can use the phone on any gsm service provider.

Answer 2

Unlocked phone: when a phone is able to be used on any sim card phone

if you saw a review on it, it was probably on a GSM phone, so that means you can use it on ATT or Tmobile in america

Answer 3

what type of phone is it?  You can unlock most gsm phones via imei unlock code here:  http://www.gsmunlocklabs.com/