समासः — compounds, and which member governs

Two padas, welded shut

2.4.71

A समास is not "two words written together." It is two finished words — each already carrying a case ending — that lose those endings and become one new word. That loss is the entire mechanism, and it is worth watching happen before anything else on this page.

सुपो धातुप्रातिपदिकयोःThe rule that does it

Compounding does not start from bare stems. It starts from a real phrase, two padas that could stand in an ordinary sentence, each already declined. 2.1.1 requires the two words to be समर्थ — mutually construable, capable of modifying one another — and 2.1.4 says the joining happens between words that end in सुप्, the ordinary nominal case endings.

Only once that phrase exists does 2.4.71 act: it elides the सुप् of both. Not one — both. And 1.2.46 gives the result its own status: कृत् words, तद्धित words and समासs are all counted as प्रातिपदिक — a nominal stem in its own right, exactly like गृह or पति on their own, ready to take one fresh ending when the sentence actually needs one.

षष्ठी — "of the house" प्रथमा — "lord"

Compounded, both endings go, and becomes one word: — declinable again, but only once, as a whole.

This is why a compound is ambiguous in a way its vigraha is not. गृहस्य पतिः can only mean one thing — the षष्ठी ending says so outright. गृहपतिः has thrown that ending away. For this particular pair the loss costs nothing, because nothing else is plausible. For other pairs — the interactive section below has one — throwing the ending away is exactly what opens the door to more than one reading.

The four kinds, by which member governs

2.1 · 2.2

Pāṇini does not classify compounds by what they mean. He classifies them by which member the whole compound tracks — which one is प्रधान, and which one is उपसर्जन, subordinate. Four answers, four kinds.

Two ways of being तत्पुरुष without a case relation

तत्पुरुष is defined broadly enough to hold two further, common sub-kinds that are not about a case relation at all.

कर्मधारयSame-case apposition

— 1.2.42. When both members would stand in the same case if left uncompounded — an adjective and the noun it qualifies, both nominative — the तत्पुरुष is called कर्मधारय instead.

द्विगुA numeral first member

— 2.1.52. A कर्मधारय-shaped compound whose first member is a संख्या — and whose sense, per 2.1.51 , is समाहार: not "four classes" but "the group of four classes," one collective thing.

अन्यपदार्थ — a meaning outside itself

2.2.23 · the evidence

बहुव्रीहि's own definition, — 2.2.23, "the remainder is बहुव्रीहि" — is famously indirect: it names बहुव्रीहि by saying what it isn't (not तत्पुरुष, not कर्मधारय, not द्विगु), rather than saying what it is. The traditional gloss on that remainder is अन्यपदार्थ — a बहुव्रीहि denotes a meaning that belongs to another word, outside the compound entirely. That is easy to state and easy to forget. The corpus proves it without meaning to.

compound	what its own parts say	what the corpus glosses it as

Look at the middle column against the right. Not one of these four words is defined as the thing its parts describe. पीताम्बर is not glossed as a kind of garment; लम्बोदर is not glossed as a kind of belly. Each is glossed as a person (or, for नीलोत्पल, a named weapon) — a referent standing entirely outside the compound's own vocabulary. Compare गृहपति in the section above: its gloss is still "a kind of lord" — the last member's own category. That contrast is the difference between तत्पुरुष and बहुव्रीहि, and it did not need to be argued for; the dictionary just does it, compound after compound.

The workhorse: तत्पुरुष by case

2.1.24 – 2.2.8

Every तत्पुरुष is named for the vibhakti its vigraha would have used on the first member — द्वितीया, तृतीया, चतुर्थी, पञ्चमी, षष्ठी, सप्तमी. Six sub-rules, and they are not equally generous.

विभक्तिः	सूत्रम्	restriction	corpus example	अर्थः

One compound, read three ways

Interactive

2.4.71 threw the case endings away, so the bare string that is left under-determines the vigraha. Pick a compound and a reading — the string never changes, only what it is taken to mean.

समासः

reading

Watch 2.4.71 happen

Step by step

The same collapse, staged: the vigraha with its endings intact, the endings elided, and the single new प्रातिपदिक that is left. Step through either compound.

What this buys you when reading

Practice

A bare compound cannot tell you which reading is meant — but the sentence around it usually can. The verb alone can rule readings out.

Check yourself

अभ्यासः

Six questions. Every one is answered by a sūtra, not by feel.

Where every form on this page comes from. Every compound is a corpus stem — of them, none typed from memory, each checked with C.has before use. Every declined word inside a vigraha — गृहस्य, पाणौ, यस्य, चतुर्णाम् — is pulled from the same 9,007-stem paradigm data the rest of this series uses. द्वितीया- and चतुर्थी-तत्पुरुष turned up no example after candidate compounds were checked against the corpus at build time — the search is embedded in the build, not asserted by the author, so a rebuild would catch it if that ever changes.