Sutra

A sutra (Sanskrit sūtra, literally 'thread') is a very short prose formula from the Indian textual tradition, composed to be committed to memory and then unpacked through commentary. The genre spans grammar (Panini's Aṣṭādhyāyī), philosophy (the Yoga Sutras of Patanjali, the Brahma Sutras), mathematics, ritual manuals, and — in the Buddhist tradition, where the Pali form is sutta — the recorded discourses of the Buddha.

The distinguishing feature is compression at the edge of intelligibility. A sutra is meant to be so brief that it cannot be understood without a teacher or a commentary; the surrounding tradition of exegesis (bhāṣya) is not an accident of transmission but part of the design. This makes the sutra an unusual quotation form for Western readers: the quoted line is usually only the ignition of the meaning, not the whole of it.

In quotation, sutras are typically cited by chapter and verse number ('Yoga Sutra I.2') because the numbering is stable across editions and commentaries. Serious writers pair the sutra with a specific commentator's reading, since two traditions can gloss the same sutra in materially different ways, and quoting the bare line implies a neutrality that the source itself does not possess.

Common mistake: treating a sutra as a stand-alone aphorism in the Western sense. A line from the Yoga Sutras isolated from its commentary tradition often reads as vague or paradoxical, because the compression assumes a reader with the commentary in hand.