Reply To: I want to use Child theme for Multiple domain.

Hello,

When you want to use the child theme, you do not need the license for it. So:

http://www.xy.com you need one license for the parent theme and no license for the child (child theme would not work without a parent)

http://www.xyz.com you need the second separate license for the parent theme and no license for the child

http://www.xyzz.com you need the third separate license for the parent theme and no license for the child

Best Regards