What does "gluten-free" means?

[Cornellius]

Hellmann´s mayo is gluten-free....what the hell does that mean???No dictionary has the word gluten. If anyone know what does it mean is spanish would be great, but if you can explain the meaning in english would be as good.
Thanks

 

[Enock]

you sure its not glutton hehe

 

[Enock]

Gluten is the protein component in wheat, oats, rye and barley

 

[Crazy K]

Many people have an intolerance (allergy) to gluten. Some people are allergic to wheat products all together.

But Enock is right, it's a protein. i just thought I'd share why something might have "gluten free"