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

Pluti is the term for the phenomenon of overlong vowels in Sanskrit; the overlong vowels are themselves called pluta. Pluta vowels are usually noted with a numeral "3" (indicating a length of three morae), ā3, ī3, ū3, ṝ3, ḹ3, also e3 (ā3i), o3 (ā3u).

Pluta vowels are recorded a total of 3 times in the Rigveda and 15 times in the Atharvaveda, typically in cases of questioning and particularly where two options are being compared. For example:

  • RV 10.129.5d adháḥ svid āsî3d upári svid āsī3t "Was it above? Was it below?"
  • AV 9.6.18 idáṃ bhûyā3 idâ3miti "Is this larger? Or this?"

The pluti attained the peak of their popularity in the Brahmana period of late Vedic Sanskrit (roughly 8th century BC), with some 40 instances in the Shatapatha Brahmana alone.

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".


  • Klaus Strunk, Typische Merkmale von Fragesätzen und die altindische 'Pluti' , Munich (1983).
  • Whitney, W. D. (2005). Sanskrit Grammar. Delhi: Motilal Banarsidass. ISBN 81-208-0620-4.