A graphical user interface element which can be used to display hierarical information, like file system directory structures or ancestry information. An example of Miller Columns in use can be found in
NeXTStep-like
file managers similar to the one that can be found at the following URL:
http://www.csn.ul.ie/~clernong/icons/fsviewer_main.jpg
If anyone has further examples of miller columns in use, especially examples outside of file managers, please post them here.