Premium Domains? Premium Domains are already registered domains. They are owned by someone and are for sale. Premium Domains have usually short-length names are easy to memorize and are valued much higher than all others. They may cost a small amount of money or even a reasonably large amount. Some other terms used, are:

• Aftermarket Domains,
• Secondary Market Domains
• High-Value Domains.

Most of these are  ".com" , ".net", ".org",  ".biz" domains. Some of them may already have serious ready/active/traffic coming in, and even remain at a high rank in Website Ranking sites, suh as Alexa. If you are lookiing for an established Domain name that is already known and has a lot of traffic already coming in, then this is a good option. In case your niche is the same or very relative to a already existing Premium Domain this can give you a "fly start" than taking all the effort from the very beginning.