Punjab is a Persian word which mean five rivers. Punj= five and aab= water/ river.
The plains between the Indus and Ganges river are called Punjab as they were irrigated naturally by the fiver rivers: Ravi, Chenab, Bias, Sutlej, Jhelum, and Sindh has seen one of the oldest civilizations in the world, The Indus valley civilization along the banks of river Indus (sindh) in present day Pakistan you can still see its ruins which were first discovered in 1922 by a team of British archaeologists.
As you can see, out of the entire Punjab only about one third was annexed to India while the remaining being Muslim majority area went to Pakistan. The district wise distribution of Pakistani and Indian Punjab is given in the following maps. In the first map the green area is the Punjab province of Pakistan while the small left handed portion in the map of India is Indian Punjab.
In 1947 the British divided Punjab between Pakistan and India. The Eastern (Indian Punjab) became the land of Sikhs (the religion of Guru Nanak who was born at Nankana (Pakistan) and preached against idol worship as practiced in the Hindu religion. Sikhs are a martial race and they made Amritsar (India) as their holy city. The famous Golden Temple is in Amritsar. An earlier prime minister of India, Indira Gandhi, fought a war with Sikhs who demanded “Khalistan” or a separate state for the Sikhs. She used tanks and heavy artillery and this sacred place of Sikh worship was badly destroyed. Thousands of Sikhs were also killed in that army operation.
Jats are the people (Punjabi) who are known traditionally to have larger built, taller in height and slightly lower in I. Q. (its a tradition to call them as having lower I.Q, there is no proof of any Punjabi Sikh or Muslim to have I.Q lower than any other ethnic people of Pakistan and India. Large number of Punjabis have also settled in Canada, UK, USA and elsewhere even before 1947. There is a tendency among Hindus to make fun of Sikhs while referring to their homeland, the Indian Punjab.
There is no truth in these beliefs however. Punjabi is a peace loving people and have been the place for mystiques, sufis, and hospitality and bravery. During the two world wars, British recruited maximum number of troops from Punjab, Jhelum and Pothohar plateau areas in particular (both in Pakistan). Some famous cities in the Pakistani Punjab are:
Lahore, Faisalabad, Multan, Sargodha, Dera Ismael Khan, Bahawalpur, Rawalpindi, Attock, Sahiwal, Qasur, Sialkot, Gujranwala, Gujrat, Okara and Jhelum; In Indian Punjab some cities of prominence are Amritsar, Ludhiana, Chandigarh, Bathinda, Faridkot, Ferozpur, Rupnagar and Patiala.