The term "crown" is used to describe the portion of your tooth that extends above the gumline - in other words, the portion of the tooth that can be seen in a healthy mouth. It is also used more colloquially to describe the dental procedure of having a prosthetic "crown" placed over a decayed, chipped, cracked, or otherwise damaged tooth.
With this dental procedure code, the prosthetic crown is seated atop an abutment, which itself is attached to a dental implant. In some procedures, an abutment is not used, and the crown is screwed directly atop the implant. The crown fitted over the tooth is made entirely of either porcelain or ceramic. This yields great cosmetic results, with porcelain creating a more natural look than the "heavier" look of full ceramic. For this reason, an all porcelain crown is typically used to on teeth within the "smile-zone," whereas a fully ceramic crown is most often used in the rear of the mouth.
Since the procedure for an abutment supported crown involves the placement of a dental implant, you may wish to read the related content concerning endosteal implants, abutments, or eposteal implants for the most complete picture of this procedure.