Compounds are words that are created by combining two or more nominal words (nouns or adjectives). English has compounds like "singer-songwriter," "air conditioner," "blackbeard," and so on.
dvandva
A compound like saṃjaya-hariṇyau ("Sanjaya and Harini") is called a dvandva ("pair") compound. The dvandva expresses a collection or group of things. In the examples below, the expressions on either side of the arrow mean the same thing.
saṃjayo hariṇī ca ⟶ saṃjaya-hariṇyau
Sanjaya and Harinirāmo lakṣmaṇaś ca ⟶ rāma-lakṣmaṇau
Rama and Lakshmana
tatpuruṣa
A compound like hariṇī-mātā ("Harini's mother") is called a tat-puruṣa ("his man"). Here, the first word in the compound describes or supports the second.
Some English examples include "passport photo" (a photo for a passport), "village music" (music from the village), "awestruck" (struck with awe), and so on. Here are some Sanskrit examples:
hariṇyā mātā ⟶ hariṇī-mātā
Harini's motherrājñaḥ putraḥ ⟶ rāja-putraḥ
A king's son, a prince
The tatpuruṣa is very broad and can support all kinds of relationships:
gṛham gataḥ ⟶ gṛha-gataḥ
Gone homedaṇḍena tāḍitaḥ ⟶ daṇḍa-tāḍitaḥ
Hit with a stickgṛhe jātaḥ ⟶ gṛha-jātaḥ
Born at home
bahuvrīhi
A compound like mahā-rathaḥ ("great-charioted") is called a bahu-vrīhi ("much-riced"). Both words together create an adjective. The bahu-vrīhi is hard to describe but easy to understand:
mahān rathaḥ yasya ⟶ mahā-rathaḥ
He who has a great chariot ("great-charioted")bahur vrīhir yasya ⟶ bahu-vrīhiḥ
He who has much rice ("much-riced")riktaḥ prakoṣṭho yasya ⟶ rikta-prakoṣṭhaḥ
He who has a bare forearm ("bare-forearmed")