Commonly abbreviated as H, height is a measurement of how tall a three-dimensional object is. For example, measurements of an object, like a computer monitor, are commonly given in D x W x H, short for Depth by Width by Height. In the illustration, the Y-axis is the height dimension.
Knowing the height of an object helps make sure that the object fits into another object. For example, if you had an enclosed computer desk, you could compare its vertical height with the height of the monitor to determine if it would fit into the desk vertically.
When measuring a three-dimensional object like a computer monitor, you'll want to get all measurements. In our example of a computer monitor and enclosed desk, the monitor may fit into the desk vertically but not horizontally (width) or have too much depth.