A banknotealso called a bill (North American English), paper money, or simply a noteis a type of negotiable promissory note, made by a bank or other licensed authority, payable to the bearer on demand.

Banknotes were originally issued by commercial banks, which were legally required to redeem the notes for legal tender (usually gold or silver coin) when presented to the chief cashier of the originating bank. These commercial banknotes only traded at face value in the market served by the issuing bank. Commercial banknotes have primarily been replaced by national banknotes issued by central banks or monetary authorities.

National banknotes are often but not always legal tender, meaning that courts of law are required to recognize them as satisfactory payment of money debts. Historically, banks sought to ensure that they could always pay customers in coins when they presented banknotes for payment. This practice of "backing" notes with something of substance is the basis for the history of central banks backing their currencies in gold or silver. Today, most national currencies have no backing in precious metals or commodities and have value only by fiat. With the exception of non-circulating high-value or precious metal issues, coins are used for lower valued monetary units, while banknotes are used for higher values.

Code of Hammurabi Law 100 (c. 17551750 BC) stipulated repayment of a loan by a debtor to a creditor on a schedule with a maturity date specified in written contractual terms. Law 122 stipulated that a depositor of gold, silver, or other chattel/movable property for safekeeping must present all articles and a signed contract of bailment to a notary before depositing the articles with a banker, and Law 123 stipulated that a banker was discharged of any liability from a contract of bailment if the notary denied the existence of the contract. Law 124 stipulated that a depositor with a notarized contract of bailment was entitled to redeem the entire value of their deposit, and Law 125 stipulated that a banker was liable for replacement of deposits stolen while in their possession.In China during the Han dynasty, promissory notes appeared in 118 BC and were made of leather. Rome may have used a durable lightweight substance as promissory notes in 57 AD which have been found in London. However, Carthage was purported to have issued bank notes on parchment or leather before 146 BC. Hence Carthage may be the oldest user of lightweight promissory notes. The first known banknote was first developed in China during the Tang and Song dynasties, starting in the 7th century. Its roots were in merchant receipts of deposit during the Tang dynasty (618907), as merchants and wholesalers desired to avoid the heavy bulk of copper coinage in large commercial transactions. During the Yuan dynasty (12711368), banknotes were adopted by the Mongol Empire. In Europe, the concept of banknotes was first introduced during the 13th century by travelers such as Marco Polo, with European banknotes appearing in 1661 in Sweden.

Counterfeiting, the forgery of banknotes, is an inherent challenge in issuing currency. It is countered by anticounterfeiting measures in the printing of banknotes. Fighting the counterfeiting of banknotes and cheques has been a principal driver of security printing methods development in recent centuries.

Massachusetts ( (listen), ), officially the Commonwealth of Massachusetts, is the most populous state in the New England region of the United States. It borders on the Atlantic Ocean and Gulf of Maine to the east, Connecticut to the southwest and Rhode Island to the southeast, New Hampshire to the northeast, Vermont to the northwest, and New York to the west. The capital of Massachusetts is Boston, which is also the most populous city in New England. It is home to the Greater Boston metropolitan area, a region influential upon American history, academia, and industry. Originally dependent on agriculture, fishing and trade, Massachusetts was transformed into a manufacturing center during the Industrial Revolution. During the 20th century, Massachusetts's economy shifted from manufacturing to services. Modern Massachusetts is a global leader in biotechnology, engineering, higher education, finance, and maritime trade.Massachusetts was a site of early English colonization: the Plymouth Colony was founded in 1620 by the Pilgrims of the Mayflower, and in 1630 the Massachusetts Bay Colony, taking its name from the indigenous Massachusett people, established settlements in Boston and Salem. In 1692, the town of Salem and surrounding areas experienced one of America's most infamous cases of mass hysteria, the Salem witch trials. In 1777, General Henry Knox founded the Springfield Armory, which, during the Industrial Revolution, catalyzed numerous important technological advances, including interchangeable parts. In 1786, Shays' Rebellion, a populist revolt led by disaffected American Revolutionary War veterans, influenced the United States Constitutional Convention. In the 18th century, the Protestant First Great Awakening, which swept Britain and the Thirteen Colonies, originated from the pulpit of Northampton preacher Jonathan Edwards. In the late 18th century, Boston became known as the "Cradle of Liberty" for the agitation there that later led to the American Revolution.

The entire Commonwealth of Massachusetts has played a powerful scientific, commercial, and cultural role in the history of the United States. Before the American Civil War, Massachusetts was a center for the abolitionist, temperance, and transcendentalist movements. In the late 19th century, the sports of basketball and volleyball were invented in the western Massachusetts cities of Springfield and Holyoke, respectively. In 2004, Massachusetts became the first U.S. state to legally recognize same-sex marriage as a result of the Massachusetts Supreme Judicial Court's decision in Goodridge v. Department of Public Health. Many prominent American political dynasties have hailed from the state, including the Adams and Kennedy families. Harvard University in Cambridge is the oldest institution of higher learning in the United States, with the largest financial endowment of any university, and Harvard Law School has educated a contemporaneous majority of Justices of the Supreme Court of the United States. Kendall Square in Cambridge has been called "the most innovative square mile on the planet", in reference to the high concentration of entrepreneurial start-ups and quality of innovation which have emerged in the vicinity of the square since 2010. Both Harvard and MIT, also in Cambridge, are perennially ranked as either the most or among the most highly regarded academic institutions in the world. Massachusetts residents have been described by the World Population Review as having the highest average IQ of all U.S. states, exceeding 104, and the state's public-school students place among the top tier in the world in academic performance. The state has been ranked as one of the top states in the United States for citizens to live in, as well as one of the most expensive.