The <dimension> CSS data type represents a <number> with a unit attached to it, for example 10px. CSS uses dimensions to specify distances ( <length> ), durations ( <time> ), frequencies ( <frequency> ), resolutions ( <resolution> ), and other quantities. The syntax of <dimension> is a <number> immediately followed by a unit which is an identifier.

Code sample

div {
  height: 200px;
  width: 50%;
  background-color: powderblue;
}