One notable feature of the agglutinative nominal system of Classical Sanskrit is the very common use of nominal compounds, which may be huge and are generative. Nominal compounds occur with various structures, but morphologically speaking they are essentially the same: each noun is in its stem form, with only the final element receiving case inflection.
Avyayībhāva
The first member of this type of nominal compound is an indeclinable, to which another word is added so that the new compound also becomes indeclinable. Examples: +, +, etc. In avyayībhāva compounds, the first member has primacy, i.e., the whole compound behaves like an indeclinable due to the nature of the first part which is indeclinable.
Tatpuruṣa (determinative)
Unlike the avyayībhāva compounds, in Tatpuruṣa compounds the second member has primacy. There are many types of tatpuruṣa. Incidentally, the word "tatpuruṣa" is itself a tatpuruṣa, while "caturthītatpuruṣa" is a karmadhāraya, being both dative and a tatpuruṣa. An easy way to understand it is to look at English examples of tatpuruṣas: "battlefield", where there is a genitive relationship between "field" and "battle", "a field of battle"; other examples include instrumental relationships and locative relationships. All these normal Tatpuruṣa compounds are called, because the case ending should depend upon the second member because semantically the second member has primacy, but actually the case ending depends upon the first member. Literally, means opposite or different case ending. But when the case ending of both members of a tatpuruṣa compound are similar, then it is called a karmadhāraya tatpuruṣa compound, or simply a karmadhāraya compound.
Dvigu
is a subtype of in which the modifying member is a number. itself is a compound : +.
Karmadhāraya (descriptive)
It is a variety of tatpuruṣa as shown above, but treated separately. The relation of the first member to the last is appositional, attributive or adverbial, e. g. is a demon in the shape of an owl.
Madhyama-pada-lopī-samāsa
It is that variety of Karmadhāraya tatpuruṣa compound in which the middle part is implied but not present for brevity. E.g.,, lit. "god-Brahmin", concatenated from "god-worshipping Brahmin".
Nañ-samāsa
Example: + =, in which 'na' when placed in an initial position becomes 'a-'. While useful in classification, this is said to be etymologically "incorrect". Historically 'a-' negation is originated from na in its weak grade, Indo-European ne is normal grade form and its weak grade is sonant ņ, which in Sanskrit becomes a or an depending on the following sound.
Upapada-samāsa
A variety of tatpuruṣa compound in which nouns make unions with verbs. These compounds can be recognized by the fact that the second part contains a verbal root : kumbham + kṛ = kumbhakāra ; śāstram + jñā = śāstrajña ; jalam + dā = jalada .
Dvandva (co-ordinative)
These consist of two or more noun stems, connected in sense with 'and'. There are mainly two kinds of द्वन्द्व constructions in Sanskrit:
Itaretara dvandva
The result of इतरेतर द्वन्द्व is an enumerative word, the meaning of which refers to all its constituent members. The resultant compound word is in the dual or plural number and takes the gender of the final member in the compound construction. For example:
रामलक्ष्मणौ rāmalakṣmaṇau, equivalent to रामश्च लक्षमणश्च rāmaś ca lakṣmaṇaś ca. It describes the sons of King Daśaratha, around whom, along with Rāma's wife Sītā, the epic Rāmayaṇa revolves.
रामलक्ष्मणभरतशत्रुघ्नाः rāmalakṣmaṇabharataśatrughṇāḥ, equivalent to रामश्च लक्ष्मणश्च भरतश्च शत्रुघ्नश्च rāmaś ca lakṣmaṇaś ca bharataś ca śatrughṇaś ca. It describes all the sons of King Daśaratha.
धातुलकारपुरुषवचनानि dhātulakārapuruṣavacanāni, equivalent to धातुश्च लकारश्च पुरुषश्च वचनं च dhātuś ca lakāraś ca puruṣaś ca vacanaṃ ca. It describes the method of describing verb inflections and conjugations.
Samāhāra dvandva
Words may be organised in a compound to form a metonym, and sometimes the words may comprise all the constituent parts of the whole. The resultant compound word exhibits समाहार द्वन्द्व, and is always neuter and in the singular number.
पाणिपादम् pāṇipādam, equivalent to पाणी च पादौ च pāṇī ca pādau ca hands two feet
According to some grammarians, there is a third kind of dvandva, called एकशेष द्वन्द्व ekashesha dvandva, where only one stem remains in the compound of multiple words: this exhibits "true" metonymy.
पितरौ pitarau, equivalent to माता च पिता च mātā ca pitā ca. Here, the only stem used is पितृ pitṛ which in dual case declines to give pitarau, or in this case pitarau. Itaretara dvandva can also be performed to give मातापितरौ mātāpitarau, and this can mean precisely the same as pitarau.
Bahuvrīhi (possessive)
Bahuvrīhi, or "much-rice", denotes a rich person—one who has much rice. Bahuvrīhi compounds refer to a compound noun with no head—a compound noun that refers to a thing which is itself not part of the compound. For example, "low-life" and "block-head" are bahuvrīhi compounds, since a low-life is not a kind of life, and a block-head is not a kind of head. Compare with more common, headed, compound nouns like "fly-ball" or "alley cat". Bahurvrīhis can often be translated by "possessing..." or "-ed"; for example, "possessing much rice", or "much-riced". In simple terms, it is a compound which is an adjective for a third word which is not a part of the compound.
Aluk-samāsa
In an aluk-samāsa, case endings do not vanish, e.g., ātmane + padam = ātmanepadam.
Āmreḍita (iterative)
A compound consisting of the same word repeated, but with the first occurrence being accented. Amreditas are used to express repetitiveness; for example, from dív we obtain divé-dive and from devá we obtain or devó-devas.
