Inpainting (image interpolation) is the process by which lost or deteriorated image data is reconstructed, but within the context of digital photography can also refer to replacing or removing unwanted areas of an image. For example, you can remove or replace:
The Inpainting Brush Tool is used to paint over (and identify) damaged or unwanted areas. Complex algorithms then take over to harvest information from the surrounding areas of the image in order to reconstruct the missing data.