Abstract
Presently the research on ageism is marked by numerous more or less diffuse definitions of the concept of ageism. Many studies investigate both the causes and consequences of ageism without a clear definition of the phenomenon. As a consequence the area is characterized by diverging research results which are hard to re-test and to compare. It is therefore difficult to obtain a framework on ageism.This article offers a conceptual clarification of ageism. Based on a review of the existing literature, a new definition of ageism is introduced. This definition is more explicit and complex than previous definitions. This has two purposes. Firstly, its clarity constitutes the foundation for higher reliability and validity in future research about ageism. Secondly, its complexity offers a new way of systemizing theories on ageism.