A standing desk, also called a stand-up desk, is basically a desk that allows you to stand up comfortably while working.
Many modern versions are adjustable so that you can change the height of the desk and alternate between sitting and standing.
These are referred to as height-adjustable desks or sit-stand desks.
Although research is still in early stages, it does appear that using a standing desk can have impressive benefits for health. It may also increase productivity.
At the very least, using this type of desk can partly negate the harmful effects of sitting too much.