Sutra (Sanskrit: सूत्र, romanized: sūtra, lit. 'string, thread') in Indian literary traditions refers to an aphorism or a collection of aphorisms in the form of a manual or, more broadly, a condensed manual or text. Sutras are a genre of ancient and medieval Indian texts found in Hinduism, Buddhism and Jainism.
In Hinduism, sutras are a distinct type of literary composition, a compilation of short aphoristic statements. Each sutra is any short rule, like a theorem distilled into few words or syllables, around which teachings of ritual, philosophy, grammar, or any field of knowledge can be woven. The oldest sutras of Hinduism are found in the Brahmana and Aranyaka layers of the Vedas. Every school of Hindu philosophy, Vedic guides for rites of passage, various fields of arts, law, and social ethics developed respective sutras, which help teach and transmit ideas from one generation to the next.
In Buddhism, sutras, also known as suttas, are canonical scriptures, many of which are regarded as records of the oral teachings of Gautama Buddha. They are not aphoristic, but are quite detailed, sometimes with repetition. This may reflect a philological root of sukta (well spoken), rather than sutra (thread).
In Jainism, sutras also known as suyas are canonical sermons of Mahavira contained in the Jain Agamas as well as some later (post-canonical) normative texts.
A 17th-century birch bark manuscript of ancient Panini Sutra, a treatise on grammar,
found in Kashmir.
The Sanskrit word Sūtra (Sanskrit: सूत्र, Pali: sūtta, Ardha Magadhi: sūya) means "string, thread". The root of the word is siv, that which sews and holds things together. The word is related to sūci (Sanskrit: सूचि) meaning "needle, list", and sūnā (Sanskrit: सूना) meaning "woven".
In the context of literature, sūtra means a distilled collection of syllables and words, any form or manual of "aphorism, rule, direction" hanging together like threads with which the teachings of ritual, philosophy, grammar, or any field of knowledge can be woven.
A sūtra is any short rule, states Moriz Winternitz, in Indian literature; it is "a theorem condensed in few words". A collection of sūtras becomes a text, and this is also called sūtra (often capitalized in Western literature).
A sūtra is different from other components such as Shlokas, Anuvyakhayas and Vyakhyas found in ancient Indian literature. A sūtra is a condensed rule which succinctly states the message, while a Shloka is a verse that conveys the complete message and is structured to certain rules of musical meter, a Anuvyakhaya is an explanation of the reviewed text, while a Vyakhya is a comment by the reviewer.