Punjab (Urdu, Punjabi: پنجاب, panj-āb, "five waters": listen (help·info)), also spelled Panjab, is the most populous of the four provinces of Pakistan. It has an area of 205,344 square kilometres (79,284 square miles) and a population of 91.379.615 in 2011, approximately 56% of the country's total population. Its provincial capital and largest city is Lahore. Punjab is bordered by the Indian states of Jammu and Kashmir to the northeast and Punjab and Rajasthan to the east. In Pakistan it is bordered by Sindh to the south, Balochistān and Khyber Pakhtunkhwa to the west, and Islamabad and Azad Kashmir to the north. 

Punjab's geography mostly consists of the alluvial plain of the Indus River and its four major tributaries in Pakistan, the Jhelum, Chenab, Ravi, and Sutlej rivers. There are several mountainous regions, including the Sulaiman Mountains in the southwest part of the province, and Margalla Hills, Salt Range, and Pothohar Plateau in the north. Agriculture is the chief source of income and employment in Punjab; wheat and cotton are the principal crops. Since independence, Punjab has become the seat of political and economic power; it remains the most industrialised province of Pakistan. It counts for 39.2% of large scale manufacturing and 70% of small scale manufacturing in the country. Its capital Lahore is a major regional cultural, historical, and economic centre.
What means five waters?
Punjab (Urdu, Punjabi: پنجاب, panj-āb, "five waters"