deriv SD cv (398) ashtadhyayi.com hei.de L 398 ETT STT a 7.1.81 ALPH OLDHOMEPAGE NEWHOMEPAGE

zap;zyanor nityam

शप्श्यनोर्नित्यम् ONPANINI 71081

When /zatR is after /zap /zyan and before /zI /GI, it takes /num.

Examples before /GI —

pacantI brAhmaNI पचन्ती ब्राह्मणी "a cooking **brAhmaNI- ब्राह्मणीॱ"
dIvyantI brAhmaNI दीव्यन्ती ब्राह्मणी "a gambling **brAhmaNI- ब्राह्मणीॱ"
dIvyantyA brAhmaNyA दीव्यन्त्या ब्राह्मण्या "by a gambling **brAhmaNI- ब्राह्मणीॱ"

before /zI —

pacantI kule पचन्ती कुले "two cooking families"
dIvyantI kule दीव्यन्ती कुले "two gambling families"
dIvyantyoH kulayoH दीव्यन्त्योः कुलयोः "of two gambling families"

The other verb stems ending in a अ are caught by < AcchInadyorn..., so their /num is optional.

What's the word nityam नित्यम् doing in the sUtra?

It means compulsorily, q.v.