An attachment to a microscope, below the stage, supporting the condenser or other accessory. ... (05 Mar 2000) ... 
(sub´stāj) the part of the microscope underneath the stage.
Type: Term Pronunciation: sŭb′stāj Definitions: 1. An attachment to a microscope, below the stage, supporting the condenser or other accessory.
the component part of a microscope below the stage, for supporting a condenser, mirror, or other accessories.