 The proper understanding of the relation in "nirvachana" analysis between a noun and some activity, expressed by a finite verb or by mention of a verbal root came to the fore through the study of Yāska's Nirukta done in the light of a model of substitution according to which model "adesha" ('substitution') takes the "sthana" ('place') of the original "sthanin" ('place-holder') under the given circumstances.