According to the Oxford Concise Dictionary, the noun engagement and the verb to engage have several different meanings. Among these, to engage can mean “to employ busily”, “to hold a person's attention”, “to bind by a promise (usually a marriage)”, or to “come into battle with an enemy”. The noun engagement can mean “the act or state of engaging or being engaged”, an “appointment with another person”, “a betrothal”, “an encounter between hostile forces”, or “a moral commitment”. The gerund engaging means to be “attractive or charming”. In the literature on security in the Asia-Pacific, engagement most commonly refers to policies regarding the People's Republic of China. However, the term has been used in many different ways leading to a great deal of confusion and uncertainty. A Business Week headline summed up the confusion: “Does ‘engagement’ mean fight or marry?”

Although one of the most important and ubiquitous terms in the Asia-Pacific security discourse, engagement is generally undertheorized. Most of the literature on the term is either descriptive or prescriptive. There is little agreement about the meaning of engagement and considerable inconsistency in its use. The New York Times noted that “there are many definitions of engagement” and described it as a “moving target”. This indeterminacy has prompted a host of scholars and officials to offer their own modified interpretations of engagement, for example deep engagement or conditional engagement. These, in turn, have arguably made for less, rather than greater conceptual clarity.

One theoretical treatment of engagement has been put forward by Alastair Iain Johnston and Robert Ross. They argue that engagement has two distinct yet complementary meanings. First, it implies adjustment on the part of status quo powers to the legitimate interests of a rising power. In this approach, conflict is minimized and peace maintained because existing powers recognize that balance of power requires the rising power to be peacefully incorporated into the international system.