In forming the feminine with the affix ṅīp the word pati always takes the substitute n in the words like sapatni etc.,
This enjoins the necessary and not optional substitution of न् for the final इ of पति, before the affix ङीप्, in the cases of certain words. The word 'nitya' is used in the aphorism for the sake of precision. Thus सपत्नी, एकपत्नी ॥ The compound of the following words with पत्नी are governed by this rule:- 1 समान 'equal' 2 एक 'one', 3 वीर 'hero', 4 पिण्ड 'a cake', 5 भ्रातृ 'brother' 6 पुत्र 'a son', and 7 दास 'a slave' (this only in the Chhandas).,