There are several terms used for the national government in India, each having its own significance and role in the working of institutions and major policy decisions. These terms are:

1. Union Government:
The Union Government is the central authority that governs the entire country. It is responsible for the administration and implementation of policies and laws at the national level.

2. Central Government:
The Central Government is another commonly used term for the national government. It refers to the governing body that has the authority to make decisions and enact laws that apply to the entire nation.

3. Federal Government:
India is a federal country, which means power is divided between the central government and the state governments. The federal government is responsible for subjects that fall under the Union List, such as defense, foreign affairs, and currency.

4. Government of India:
This term refers to the collective body of elected representatives and officials who are responsible for governing the country. It includes the President, Prime Minister, Council of Ministers, and various government departments.

The national government in India plays a crucial role in the working of institutions and making major policy decisions. Here is how it functions:

1. Legislative Function:
The national government is responsible for the enactment of laws in the country. It consists of the Parliament, which is divided into two houses - the Lok Sabha (Lower House) and the Rajya Sabha (Upper House). The government introduces bills, debates them, and passes laws that affect the entire nation.

2. Executive Function:
The national government is responsible for the execution and implementation of policies and laws. It is headed by the President, who is the ceremonial head of the state, and the Prime Minister, who is the head of the government. The Council of Ministers, led by the Prime Minister, assists in the implementation of policies and decisions.

3. Policy Decisions:
The national government formulates and implements major policies that impact the entire country. These policies cover various sectors such as education, healthcare, economy, defense, and infrastructure development. The government takes into account the needs and aspirations of the people while making these policy decisions.

4. Administrative Function:
The national government is responsible for the administration of the country. It oversees the functioning of various government departments and agencies, ensuring the smooth running of the nation. The administrative machinery at the national level is responsible for executing policies and delivering services to the citizens.

In conclusion, the national government in India is referred to by various terms such as the Union Government, Central Government, Federal Government, and Government of India. It plays a vital role in the working of institutions and making major policy decisions. Through its legislative, executive, and administrative functions, the national government ensures the smooth functioning and development of the country.