The Fifth Veda (pañcama veda) is a term that refers to a number of post-Vedic texts of Hinduism that don't belong to any of the four Vedas, but, despite this, have a status similar to that of the Vedas. The idea of the Fifth Veda is ancient and first appears in one of the early Upanishads - "Chandogya-Upanishad" (7.1.2), which states that Fifth Veda are "Itihasas and Puranas" (itihāsa purāṇaṃ pañcamaṃ vedānāṃ). Later, the term "Fifth Veda" began to be used to refer to other texts (or a group of texts) in Sanskrit and other Indian languages, Prakrits.
The Mahabharata speaks about itself as a new Veda of a new era, which is on a par with the four canonical Vedas (and sometimes even higher) and intended for all people. Another Hindu epic, Ramayana, also calls itself the Fifth Veda. Similar statements are contained in the Puranas, which speak about themselves as about Fifth Veda or as "Purana-Veda". The Bhagavata-Purana explains the statement of the Chandogya-Upanishad about the Fifth Veda. It says that after the four Vedas emerged from the four mouths of Brahma, the Fifth Veda - the "Itihasa-Purana" simultaneously came out from all of his mouths. Then the Bhagavata-Purana declares itself to be the most important of the Puranas, explaining this by the fact that it was the last text compiled by Vyasa. The Skanda-Purana also states that the Puranas are the Fifth Veda.
The fifth Veda also calls itself the ancient treatise on music and theatrical art Natya-Shastra (1.4), which is part of the "Gandharva-Veda" - the Upaveda of the Sama-Veda. The Natya-Shastra states that its author is Brahma and that it absorbed elements from the other four Vedas, but, unlike them, is open to all castes. Behind this is the idea that theatrical and musical performances based on stories from sacred texts are spiritual and lift up the consciousness of artists and spectators to a transcendental level. The Fifth Veda is also called Ayurveda, a treatise on traditional Indian medicine. Tantrics believe that the Fifth Veda for the current age of Kali Yuga is the Agamas and Tantras.
The term Fifth Veda is also used to refer to a number of texts in Indian languages. For example, the 17th century Hindi poem "Rama-charita-manasa", which is an adaptation of the Ramayana epic and is considered by some Hindus as equal to the four Vedas in the Kali Yuga.
In South India, the status of the Fifth Veda has a number of sacred texts in Tamil, which are called the "Tamil-Veda" or "Dravida-Veda". The Fifth Veda is called the poem of the Tamil Vaishnava saints alvars "Tiruvaimoli" and in general the whole "Divya-prabandham", whose "Vedic" status is recognized in the secular treatise of the XIV century "Lilatilakam", by the Kerala grammar Manipravalam. Just as in the case of the Natya-Shastra, the authors who assigned the status of the Fifth Veda to the Tiruvaimoli poem argued that, unlike the four Vedas intended for study by the Brahmins, this new Tamil-Veda was available to all the varnas of the Hindu society.
Similarly, the Tamil Shaivites assigned the status of the Tamil-Veda to the collection of hymns called "Tevaram". Declaring "Tevaram" as a "Tamil-Veda", Tamil Shaivites tried to make it an alternative to the Sanskrit Vedas, whereas Tamil Vaishnavs, in a similar case, presented the Alvar hymns not as an alternative to the original Vedas, but as an analogous sacred text. In the work "Tiruvalluvamalai" (possibly dating back to the X century), the treatise "Tirukkural" is called the Fifth Veda.