So far we’ve studied three different ways of making new words.
1. By adding a suffix to the verb,
2. By adding a prefix to the noun, and
3. By adding a suffix to a non-verb. Now let us consider the fourth kind, which is the compound words.

Compound words are basically formed by combining two nouns to create a new noun. In English, a compound word includes two or three words but in Sanskrit, it can exceed over 30 words!
Compounds have been an essential part of Sanskrit language. They are unique as even though consisting of several words they are considered a single unit. In Sanskrit, grammarians have been researching on compounds for over several years which have led to the enormous development of compounds, the proof of which can be considered by extensive use of them.
So let us take a look at our first compound.

तस्य पुरुषः → तत्पुरुषः
tasya puruṣaḥ → tatpuruṣaḥ (His servant)

It is called the tatpurusha compound. You can see this compound appear almost in every verse of Bhagavad Gita. There are two types of tatpurusha: case 1 and case 6. So let us take a look at them.
Case 1 tatpurusha

कृष्णो हस्तः → कृष्णहस्तः
kṛṣṇo hastaḥ → kṛṣṇahastaḥ
Black hand

नरः सिंहः → नरसिंहः
naraḥ siṃhaḥ → narasiṃhaḥ
Man-lion; “he who is both a man and a lion,” i.e. narasimha

A case 1 tatprursha occupies the subject position in the sentence.

Case 6 tatpurusha
The word tatpurusha is originally a case 6 tatpurusha word itself. The word is formed such that it gives a sense of belonging; ‘tasya puruṣaḥ’ (his servant). Some other English examples will help you to understand it better.

– A patch of cabbages → cabbage patch
– The leader of the world → world leader
– Bar of iron → iron bar

Unlike the English structure of the compound, the Sanskrit compounds are always written together. They are never written separately.