भस्य टेर्लोपः

Operational rule vidhi

The टि of the भसंज्ञक अङ्ग of पथिन्, मथिन् and ऋभुक्षिन् is removed.

Word by word (padaccheda)

Target ṣaṣṭhī · ekavacanaTarget टेः ṣaṣṭhī · ekavacanaSubstitute / term prathamā · ekavacana

Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.

Dotted words are technical terms. Hover or tap one to see its card.

Full reading

टेः

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

As a rewrite rule (sketch from case endings)

टेः →

Replace bhasya ṭeḥ with lopaḥ. Inherited words (anuvṛtti) may add further conditions.

Commentary

The last vowel, with the consonant that follows it, is dropped in . पथिन् 2. मथिन् and 3. ऋभुक्षिन् before a weak case-ending beginning with a vowel (before which the अङ्ग (stem) is called भ -- यचि भम् 1.4.18.
As पथः, पथा, पथे, मथः, मथा, मथे, ऋभुक्षः, ऋभुक्षा, ऋभुक्षे ॥ The anuvritti of sarvanamasthana, of course, is inappropriate here: though its anuvritti is current as will be seen in the next sutra.

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