The main difference between altimeter and cabin altimeter is the place where they take their pressure:

Altimeter takes the pressure from static ports, while cabin altimeter takes it's pressure from the cabin.

There isn't one because it is a noun

The altimeter setting region refers to the area of an airport where a specific altimeter setting is in use for all aircraft operating within that region. This is crucial for ensuring accurate altitude readings and maintaining safe vertical separation between aircraft. Pilots must set their altimeters to the correct setting in order to accurately determine their altitude above mean sea level.

true altitude at field elevation.

My GPS instrument contains a barometric altimeter.