the arm
it supports the upper part of the microscope where the eyepiece, draw tube , body tube and the objectives is placed .
The microscope's upper part consists of the observation tube, the eyepiece, and the illuminator. These components work together to allow users to view the magnified specimen clearly and with adequate lighting. The support for the upper part of the microscope often includes an arm or stand to ensure stability and proper alignment of these components.
the arm
The base of a microscope supports the weight of the entire microscope. It provides stability and balance to prevent the microscope from tipping over during use.
The arm or the frame of the compound microscope supports the body tube.
The arm supports the body tube.
It allows to tilt the upper part of the microscope
the stage
clips
The stage
The base of the microscope supports the entire instrument and provides stability. Additionally, the arm holds the upper parts of the microscope, such as the stage and eyepiece, in place. Both the base and arm work together to support the entire body of the microscope.
If you are talking about a microscope - it is called the stage.