Śāstra is Sanskrit for rules in a general sense. The word is generally used as a suffix in the context of technical or specialized knowledge in a defined area of practice; e.g. Shastra (physics), Shastra (chemistry), Jeeva Shastra (biology), Vastu Shastra (architectural science), Shilpa Shastra (science of sculpture), Artha Shastra (economics), and Shastra (political science). In essence, the is the knowledge which is based on principles that are held to be timeless. Shastra means suffix 'logy' for the subjects; like in English language suffix word 'logy' (e.g. ecology, psychology etc.), 'Shastra' is suffix. it means scientific and basic knowledge on particular subject.