How nouns are formed in Sanskrit. Words like खग, द्विज, द्विप, वारिज, वारिद, पयोद, etc have derivations. But how are the words like गज, अश्व, बालः formed? Are they too formed from dhatus? How are the various types of nouns in Sanskrit formed? What are the rules that are applied in this?
There are two kinds of nominal bases(प्रातिपदिक) in Sanskrit -
1- Those who have got clear derivation.In them the division of root and suffix is quite visible and simply inferable. These are व्युत्पन्न प्रातिपदिक (derived bases) .
2- second are those who unlike the first have very nebulous division.And after division the meaning of root and
suffix is not fully compatible with the undertaken word. These are called अव्युत्पन्नप्रातिपदिक .
Regarding अव्युत्पन्नप्रातिपदिक some grammarians think that they are quite underivable. And they are not constituents of any root or suffix. Trying to derive them is futile and just for pedantic amusement.
But Scholars of the Nirukt vedaang = nairukt and a fraction of grammarians are of the view that all the Nominal bases are derived from the verbal roots. Every word (even the indeclinable=avyaya) is related to some verb.
Thus to derive all the word is a sacred duty for them.(See the first chapter of nirukt of maharshi yaask )
There is an ancillary book of ASTaadhyaayi ascribed to His Highness Panini deals with derivation of these अव्युत्पन्नप्रातिपदिकs. It is called uNaadi-sUtr. This book serves the purpose competently as it specifies roots and suffixes with all the irregular changes in अव्युत्पन्नप्रातिपदिकs. Besides this Some Sanskrit dictionaries also provide the derivations mainly वाचस्पत्यम , शब्दकल्पद्रुम and that of Apte.
I here provide the derivations of some words-
गज – गज+अच (one who is intoxicated)
अश्व – अश्नुते अध्वानं ( अश+kvan )= that who strides on the way. ,
बालः- बल+ण (a growing one )

