अनाप्यकः

Operational rule vidhi

The 'इद्' part of the word 'इदम्' is converted to अन् when followed by a विभक्तिप्रत्यय of तृतीया to सप्तमी. But this conversion does not happen if the word इदम् has a ककार in it.

Word by word (padaccheda)

Word अन Right context saptamī · ekavacanaTarget अकः ṣaṣṭhī · ekavacana

Word Case not marked in the source data.
Right context Saptamī (7th case): "when X follows", the operation applies to what precedes (1.1.66 तस्मिन्निति निर्दिष्टे पूर्वस्य). Also a condition or domain ("in the sense of").
Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).

Dotted words are technical terms, dashed ones pratyāhāras (names for classes of sounds or affixes). Hover or tap one to see its card.

Full reading

अन अकः

Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.

Commentary

अन is substituted for the इद् of इदम् in the Instrumental -3rd case singular and the cases that follow, provided that the augment अकच् is not added.
As अनेन, अनयोः ॥ Why do we say "not when क is added by 5.3.71"?
Observe इमकेन, इमकयोः ॥ The word आप् (आपि) in the sutra is a pratyahara, formed with the आ of टा (Instrumental Singular), and प् of सुप् (Locative Plural).

Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.