The syllable Aum (ओ३म्) is rendered by the Arya Samaj using pluti.

Pluti is the term for overlong vowels in Sanskrit. Pluti vowels are usually noted with a numeral "3" (indicating length of three morae), ā3, ī3, ū3, ṝ3, ḹ3, also e3, o3.

Pluti is recorded only in two instances in the Rigveda, representing the intonation of a question, both in the late tenth book.

• 10.146.1d ná tvā bhîr iva vindatī3ṁ "are you not afraid?"
• 10.129.5d adháḥ svid āsî3d upári svid āsī3t "was it above? was it below?"

The pluti reaches the peak of its popularity in the Brahmana period of late Vedic Sanskrit (roughly 8th century BC), with e.g. some 40 instances in the Shatapatha Brahmana. The Astadhyayi records rules for pluti in spoken language, for example 8.2.82 praty-abhi-vādé-á-śūdre "[the last syllable becomes pluti] when replying to the greeting of a non-shudra".

Literature

• Klaus Strunk, Typische Merkmale von Fragesätzen und die altindische 'Pluti' , Munich (1983).