Gift of singing or just a good mimic?

I hear the expression a lot but I never really understood what it meant. What is the difference between holding a tune and actually being able to sing? How can one tell if they're able to sing or they're just holing a tune and if they're just holding a tune does that mean they can't be trained to sing well? When I sing people tell me I have a nice tone and that I sound unique and cool. What is the difference between having a nice tone and being able to sing or is there a difference? Because, when I record myself singing on my Nikon, I feel it falls a little short of my expectations (probably because I'm comparing myself). I was given the advice to take voice lessons to help train my breathing and my voice so one day I can become a international legend. And I'm not just saying this, I'm dead serious. LOL

Get some voice lessons put your heart into it, you'll learn the difference.

The gift (ie.talent) of singing would mean that a lot of people would listen to you without training. A lot of famous singers probably have never had the gift/ability, but have practiced and got lucky.