Mapping
The relationship between the elements of two sets of things.
Mapping helps you understand what controls will do
When controls are mapped to the layout of the devices being controlled, it is easier to determine how to use them.
For example, rotating a steering wheel clockwise or counter-clockwise steers the vehicle right or left. Or the layout of a rooms' switches are mapped to the location of ceiling lights they control.
Natural mapping
Spatial analogies, such as moving an interactive element up or down in order to increase or decrease the value of another element, will decrease the time it takes to understand it.
Origin
Mapping is a technical term that was borrowed by researcher, professor and author Don Norman from mathematics to refer to the relationship between the elements of two sets of things. It is one of six concepts required to support discoverability and understanding.