The word intelligence forms part of own ordinary stock of words which we use everyday. In the field of psychology too, the word intelligence finds a fairly comprehensive use. In fact, there areas many definitions of intelligences as there are writers on the subject. On account of the different ways in which intelligence is interpreted, it has become less acceptable and more exposed to criticism by psychologists. Nevertheless, it is traditionally acknowledged by the parents and teachers that intelligence is the most important single variable which affects success in school and in life. In general terms, intelligence means the manner with which an individual deals with facts and situations. First, intelligence is defined interns of observable objective behaviour. Second, most definitions refer both to an individual’s capacity to learn and to knowledge that has already been acquired. Many definitions also suggest that the ability to adapt to the environment is a sign of intelligence. A variety of definitions on intelligence have been suggested by the psychologists which can be classified into at least four distinct groups as follows.