One of the most critical steps in the test development process is defining the construct, or the knowledge, skills, or abilities, to be assessed. This foundational step provides the basis for initial assumptions about the meaning of test scores and serves as a reference for subsequent validity research. In this paper, we describe the purpose of the redesigned TOEIC Bridge assessments to measure all four communication skills and elaborate the theoretical basis of its construct definition. We also describe how an evidence-centered design (ECD) approach was used to develop the redesigned TOEIC Bridge assessments and the first stage of that approach, the domain analysis. The domain analysis begins by elaborating a clearer definition of the context in which language is evaluated by the redesigned TOEIC Bridge assessments, “everyday adult life.” Next, we review research literature and relevant language proficiency standards to highlight the knowledge, skills, and abilities relevant to basic to intermediate English proficiency for everyday adult life. This information is synthesized in the construct definitions for reading, listening, speaking, and writing ability for basic to intermediate levels of general English proficiency in the context of everyday adult life.