उपमानादप्राणिषु

Operational rule vidhi

The affix टच् comes after the word श्वन् ending in a तत्-पुरुष समास when another thing not being a living object is compared with it.

Word by word (padaccheda)

Left context उपमानात् pañcamī · ekavacanaRight context अप्राणिषु saptamī · bahuvacana

Left context Pañcamī (5th case): "after X", the operation applies to what follows (1.1.67 तस्मादित्युत्तरस्य). Also used for limits and sources.
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").

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

Full reading

उपमानात् अप्राणिषु

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

Commentary

The affix टच् comes after the word श्वन् ending in a तत्-पुरुष समास when another thing not being a living object is compared with it.
Thus आकर्षः श्वेव = आकर्षश्वः 'a dog-like bow'. फलकश्वः "a dog-like blade". This compounding takes place by 2.1.56.

Why do we say "when something is likened to it"? Observe न श्वा = अश्वा लोष्टः "a clod of earth which is not a dog". This is not a very happy counter-example of Kasika : for in the case of नञ् Tatpurusha compound there is express prohibition taught in 5.4.71. The proper example should be निःश्वालोष्टः ॥ Why do we say "when the thing compared is not a living being" ? Observe वानरः श्वेव = वानरश्वा "a dog-like monkey".

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