Glass tables is the name Splunk gives to certain dashboard styles, such as in ITSI, where you create a glass table that can surface one or more values derived from searches and which can be 'placed' anywhere on the table. Compare that with the standard Splunk dashboard, where the layout is divided into rows and panels, where there is little control over their placement.
A single pane of glass is a concept that expresses the idea of being able to view a number of components in a single view.
So, an ITSI 'glass table' could then be described as a means to provide a 'single pane of glass' through which to view metrics and information that make up separate parts of the business.
