You can understand the concept "adult education" better if you first understand the concept 'adult' very clearly. We will therefore focus first on "adult". In simple terms, we can define "adult" as a person who has attained physical, mental, emotional and social maturity or legal age for marriage, or for franchise or voting right. But can we say for certain that every person who has attained physical maturity only, or legal age of adulthood can be considered to be mature adult of that society or country? Or can we say at what age a person will definitely becomean adult, in terms of maturity? The answer is 'No'. But at the same time, as AdultEducation:The Basic mentioned above, we can be sure of one thing that we are all adults with different Concept, Terms, Features and Objectives levels of maturity and belong to the most significant and productive age group - physically, socially, mentally, economically, politically, morally culturally, and so on. Nevertheless, we need to remember that maturity is an endless process and in general it increases with one's age, experience and knowledge. In the context of adult education, the concept 'adult' remained inadequately defined because of the multiplicity of criteria used in defining it. The Oxford Advanced Learner's Dictionary (1995) defines adult as: