In this issue of Alzheimer's & Dementia, Sweeney et al.  propose to extend the recently published NIA-AA Research Framework  by incorporating measures of vascular dysfunction as putative AD biomarkers. Although we strongly agree with the importance of a wide range of vascular factors in the development of cognitive decline, the authors misunderstand a central issue addressed in the framework: the fundamental definition of Alzheimer's disease (AD) and its distinction from the terms “Alzheimer's clinical syndrome” and dementia. We propose these terms to distinguish between the pathological features of the disease and its clinical consequences. Although there is extensive evidence that vascular factors contribute to the Alzheimer's clinical syndrome and dementia, the evidence that they contribute to AD pathological changes is limited.