Hindusim is not something to which one can give one p[lain defination. What this religion is a religion full of diversity. Thoese who belive is caste system are also hindu and those who don't believe in it are also hindus.Those who believe in idol worship are also hindus and those who are opposed to it are also hindus.Those who belive in Karam Kand r also hindu and those who r opposed 2 it r also hindus. Beliefing in one God or in 36 crore muliple god will have no effect.Beliving in Vedas or not makes no effect. Astik means those who belief in the authority of vedas and Nastik means those who do not belif in the authority of vedas.(not athesit it means aniesharwad in hindu Philosophy).Tolrance,divercification and universal Brotherhood is the essanvce of Hinduism.Having said so pl. do note that not all beleif like that .Diffrent people have diffrently interpted hinduism diffrently .JAKO RAHI BHAWNA JAISI ,TEEN DEKHI PRABHU MURAT TESI and this is true about all religions.