Pluti is the term for overlong vowels in Sanskrit

Sanskrit

Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...

. Pluti vowels are usually noted with a numeral "3" (indicating a length of three morae

Mora (linguistics)

Mora is a unit in phonology that determines syllable weight, which in some languages determines stress or timing. As with many technical linguistic terms, the definition of a mora varies. Perhaps the most succinct working definition was provided by the American linguist James D...

), , also .

Pluti vowels are recorded a total of 3 times in the Rigveda

Rigveda

The Rigveda is an ancient Indian sacred collection of Vedic Sanskrit hymns...

 and 15 times in the Atharvaveda

Atharvaveda

The Atharvaveda is a sacred text of Hinduism and one of the four Vedas, often called the "fourth Veda"....

, typically in cases of questioning and particularly where two options are being compared. For example:

• RV 10.129.5d "Was it above? Was it below?"
• AV 9.6.18 "Is this larger? Or this?"

The pluti attained the peak of its popularity in the Brahmana

Brahmana

The Brāhmaṇas are part of the Hindu śruti literature. They are commentaries on the four Vedas, detailing the proper performance of rituals....

 period of late Vedic Sanskrit

Vedic Sanskrit

Vedic Sanskrit is an old Indo-Aryan language. It is an archaic form of Sanskrit, an early descendant of Proto-Indo-Iranian. It is closely related to Avestan, the oldest preserved Iranian language...

 (roughly 8th century BC

8th century BC

The 8th century BC started the first day of 800 BC and ended the last day of 701 BC.-Overview:The 8th century BC was a period of great changes in civilizations. In Egypt, the 23rd and 24th dynasties led to rule from Nubia in the 25th Dynasty...

), with some 40 instances in the Shatapatha Brahmana

Shatapatha Brahmana

The Shatapatha Brahmana is one of the prose texts describing the Vedic ritual, associated with the Shukla Yajurveda. It survives in two recensions, Madhyandina and Kanva , with the former having the eponymous 100 adhyayas,7624 kandikas in 14 books, and the latter 104 adhyayas,6806 kandikas in 17...

 alone.

The Astadhyayi records rules for pluti in spoken language, for example 8.2.82 "[the last syllable becomes pluti] when replying to the greeting of a non-shudra".