substage

The part of a microscope located below the stage on which attachments are held in place.

An attachment to the compound microscope, placed beneath the ordinary stage, and used to support the achromatic condenser, the polarizing prism, etc.

In geology, one of the subdivisions of a stage or group.

The stage, below the main stage of a microscope, to which attachments are fixed.

A stage making up part of a larger stage.