Tabletop Exercise definition in Computer Security terms:
Definition(s): A discussion-based exercise where personnel with roles and responsibilities in a particular IT plan meet in a classroom setting or in breakout groups to validate the content of the plan by discussing their roles during an emergency and their responses to a particular emergency situation. A facilitator initiates the discussion by presenting a scenario and asking questions based on the scenario.
Source(s): NIST SP 800-84
reference: CSRC Glossary