"Floating shelves" refers to shelves that are mounted to a wall without any visible brackets or support. They give the illusion of being "floating" as they appear to be hanging on the wall without an obvious means of support. Full definition
Take advantage of the wall space next to your vanity with floating shelves for all of the items you use often. (listotic.com)
Install a few levels of floating shelves for instant storage space. (livingroomideas.com)
Create a focal point on a plain wall by using a panel of patterned wallpaper behind a dresser and add floating shelves above to display interesting accessories. (idealhome.co.uk)