Contending that the four commonplaces of defensible educational thought (the learner, the teacher, the milieu, and the subject matter) do not deal with the complexities of time and its implications for curriculum and instruction, this paper presents time as a crucial element in curricular deliberation. Various aspects of time in the school setting are presented and their implications for curriculum and instruction are discussed. A distinction is made between instructional time, curricular time, sociological time, and experienced, personal time. These distinctions do not represent a full and comprehensive framework for the study of time, but serve as constructs guiding the discussion of time as a commonplace in education. The paper argues that time constitutes a special commonplace, not to be subsumed under the four commonplaces mentioned above. Part of the potential knowledge base and body of experience needed to represent this commonplace is noted, and implications for research, curriculum development, and teacher education are made. A three-page list of references concludes the document. (SY)