The word Veda is significantly employed to designate those ancient Sanskrit works, in which is laid the foundation of Brahmanic belief. These works were originally three in number, i.e. the Rig Veda, the Sama Veda, and the Yajur Veda as is clear from the frequent mention of traividya or the triple science in ancient Sanskrit literature of the Indian scriptures.
The prayers in meter are called Rik, and those in prose are denominated yajus, while those intended to be chanted are named saman. The triple Veda is comprehended under the name of Mantra; and the complete collection of hymns, prayers and thanksgivings, belonging to a Veda is called the Samhita.
But at a more subsequent period a fourth Veda was added to them; though it was never held as sacred as its predecessors were.
However, they are now commonly four in number, viz. Rig Veda--Veda of hymns; the Sama Veda--the Veda of chants; the Yajur Veda-- the Veda of sacrificial formulas; and the Atharva Veda--Veda of incantations.
To be continued/-