As modern society ages rapidly, the number of people with dementia is sharply increasing. Direct medical costs and indirect social costs for dementia patients are also increasing exponentially. However, the lack of social awareness about dementia results in difficulties to dementia patients and their families. So, understanding dementia is the first step to remove or reduce the stigma of dementia patients and promote the health of our community. Alzheimer's disease is the most common form of dementia. The term, ‘Alzheimer's disease’ has been used for over 100 years since first used in 1910. With the remarkable growth of science and medical technologies, the techniques for diagnosis and treatment of dementia have also improved. Although the effects of the current symptomatic therapy are still limited, dramatic improvement is expected in the future through the continued research on disease modifying strategies at the earlier stage of disease. It is important to look at the past to understand the present and obtain an insight into the future. In this article, we review the etymology and history of dementia and previous modes of recognizing dementia. We also review the historical developments leading to the terminology of Alzheimer's disease.