By the Science of Definition, Nirukta Sastra, Bhagavan Yaska, meant the definition of Vedic concepts and the refutation of Non Vedic concepts. Rightly so, Nirukta Sastra, vasti tasya niruktam tu veda nirvachanam sphutam , has been referred to as the Ears of Veda Purusha, Srotha muktham Niruktham !