Length is the distance from one point to another. It can be measured in units such as meters, centimeters, or inches.
Width is the distance from one side of an object to the other. It can be measured in the same units as length.
Height is the distance from the bottom of an object to the top. It can also be measured in the same units as length and width.
Time is the progression of events from the past to the present and into the future. It can be measured in units such as seconds, minutes, hours, days, and years.
Some theories in physics suggest that there may be more than four dimensions, but these dimensions are not yet proven to exist.