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 screwed directly atop the implant, and an abutment is NOT used. The crown secured to the implant 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 on teeth within the "smile-zone," whereas a fully ceramic crown is most often used in the rear of the mouth.
For more information about dental implants, you may wish to read the related content concerning endosteal implants, abutments, or eposteal implants for the most complete picture of this procedure.