Shastra

Śāstra (Sanskrit: शास्त्र, romanized: Śāstra pronounced [ɕaːstrɐ]) is a Sanskrit word that means "precept, rules, manual, compendium, book or treatise" in a general sense. The word is generally used as a suffix in the Indian literature context, for technical or specialized knowledge in a defined area of practice.

Śāstra has a similar meaning to English -logy, e.g. ecology, psychology, meaning scientific and basic knowledge on a particular subject. Examples in terms of modern neologisms include

In Western literature, Śāstra is sometimes spelled as Sastra, reflecting a misunderstanding of the IAST symbol 'ś', which corresponds to the English 'sh'.

The word Śāstra literally means "that which has been instructed/decreed", from the root √śās- which means "instruction/decree" combined with the ṣṭra-suffix.

Śāstra commonly refers to a treatise or text on a specific field of knowledge. In early Vedic literature, the word referred to any precept, rule, teaching, ritual instruction or direction. In late and post Vedic literature of Hinduism, Śāstra referred to any treatise, book or instrument of teaching, any manual or compendium on any subject in any field of knowledge, including religious. It is often a suffix, added to the subject of the treatise, such as

In Buddhism, a "śāstra" is often a commentary written at a later date to explain an earlier scripture or sutra. For example, Yutang Lin says that a text written by him and not given by Buddha, cannot be called a "Sūtra"; it is called a "Śāstra". In Buddhism, Buddhists are allowed to offer their theses as long as they are consistent with the Sūtras, and those are called "Śāstras."

In Jainism, the term means the same as in Hinduism. An example of Jaina Śāstra is the 12th-century Yoga Śāstra of Hemchandracharya.

Śāstra is sometimes the root of compounded Sanskrit words. A custodian of Śāstra, for example, is called Śāstradhāri (Sanskrit: शास्त्रधारी).