I have a wedding ring with the following markings , what does 21k AAA on a gold ring means?

The 21k would indicate its 21 karat gold assuming it was a US Market ring. European market tends to stamp percentage of cold rather than Karat rating.

Taken from Understanding Gold Markings & Purity (http://www.sellgoldhq.com/understanding-gold-markings-purity/)

I assume the AAA is a marking of the Goldsmith. Haven't found information on that yet.