‘Ved’ means Knowledge. They are said to be the Divine Knowledge of God.
The vedic Mantras are said to pervade the cosmos and are ‘heard’ by the Rishis and given to us. Hence they are called as ‘Sruti’ or ‘Anusravam’. In tamil, they are known as ‘Ezhuthaa kiLavi’ (unwritten verses).
Vedas are known as ‘Thrayi’ because there are three major branches – Rig, Sama and Yajur.
The other reason behind that name is that they are in the form of ‘Gadhya’ (Prose), ‘Padhya’ (Poetry) and Gana (music).
Vedas convey messages in a subtle manner rather than in a blunt manner. Hence they are known as ‘marai’ (hidden) in tamil language.
Vedas prescribe the rules for life. Hence they are known as ‘Nigamam’.
Vedas are called ‘AmnAyam’ because they are studied and practiced regularly and are handed over to the disciple (sishya) from a master (guru) in succession.