Sacred text
Śāstra
is a Sanskrit term used to denote 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, Bhautika Shastra (physics), Rasayana Shastra (Chemistry), Jeeva Shastra (Biology), Vaastu Shastra (architectural science), Shilpa Shastra (science of sculpture) and Artha Shastra(Economics), Neeti Shastra (political science). In essence, the shaastra is the knowledge which is based on principles that are held to be timeless.
Shastra is also a by-word used when referring to a scripture. Extending this meaning, the shastra is commonly used to mean a treatise or text written in explanation of some idea, especially in matters involving religion. In Buddhism, a shastra is often a commentary written at a later date to explain an earlier scripture or sutra.