The phrase “multi-domain operations” (known as MDOs) is now pervasive in current military writings and analysis. Unfortunately, most authors fail to define it, leading to confusion. Worse, it can seem as if people are discussing the same set of issues when they are not. This paper attempts to rectify the situation, examining each component word and then the phrase as a whole.
Warfighting in a single domain is about gaining access to the domain in question, controlling the domain, and exploiting that control to create effects. However, multi-domain operations are more than operations in adjacent domains. To possess meaning as a distinct phrase, there must be some relationship in the access, control, and exploitation of the domains. Therefore, this paper argues that multi-domain operations are a set of tactical actions taken in one domain in order to enhance the access, control, or exploitation of one or more different domains. There are two types of multi-domain operations. First, a set of tactical actions that could exploit two or more domains to create effects on a target or objective simultaneously—convergence. Second, a multi-domain operation could gain access and control in one domain in order to create opportunities in a separate domain— establishing windows of domain superiority. True MDOs require a common language, integrated capabilities, packaging of these multi-domain capabilities, and the elimination of classification stovepipes.