Definition of AVAILABILITY. 1. : the quality or state of being available. 2. : an available person or thing.
Definition of EXECUTIVE OFFICER. : the officer second in command of a military or naval organization or vessel. ADVERTISEMENT. the officer second in command of a military or naval organization or vessel. ADVERTISEMENT.
The executive officer is the billet of the officer who is second-in-command at the company/battery, battalion/squadron, and Marine expeditionary unit (MEU)/regiment/aviation group (i.e., Marine Aircraft Group, Marine Air Control Group, and Marine Wing Support Group) level.