Through ages, there have been several attempts to generate 'a universally acceptable definition of law'. But in 1972, British jurist Baron Hampstead (Dennis Lloyd, Baron Lloyd of Hampstead; 1915–1992) concluded that no such definition could be produced. Hilaire and White, in their book Textbook on Jurisprudence said that the question "what is law?" has no simple answer. Glanville Williams opined that the meaning of the word 'law' depends on the context in which that word is used.

So, it is clear that it is quite difficult to define law comprehensively in short. In that case, before trying to understand 'law', let's look into some popular definitions of the term:

Collins Dictionary: The law is a system of rules that a society or government develops in order to deal with crime, business agreements, and social relationships.

Merriam-Webster: a binding custom or practice of a community : a rule of conduct or action prescribed or formally recognized as binding or enforced by a controlling authority

Encyclopaedia Britannica: Law, the discipline and profession concerned with the customs, practices, and rules of conduct of a community that are recognized as binding by the community. Enforcement of the body of rules is through a controlling authority.

Legal Dictionary: A body of rules of conduct of binding legal force and effect, prescribed, recognized, and enforced by controlling authority.

Oxford (Lexico) Dictionary: The system of rules which a particular country or community recognizes as regulating the actions of its members and which it may enforce by the imposition of penalties.

Wikipedia: Law is commonly understood as a system of rules that are created and enforced through social or governmental institutions to regulate behavior, although its precise definition is a matter of longstanding debate. It has been variously described as a science and the art of justice.

School of Law, University of Kashmir: Law is an instrument which regulates human conduct/behavior. Law means Justice, Morality, Reason, Order, and Righteous from the view point of the society. Law means Statutes, Acts, Rules, Regulations, Orders, and Ordinances from point of view of legislature. Law means Rules of court, Decrees, Judgment, Orders of courts, and Injunctions from the point of view of Judges. Therefore, Law is a broader term which includes Acts, Statutes, Rules, Regulations, Orders, Ordinances, Justice, Morality, Reason, Righteous, Rules of court, Decrees, Judgment, Orders of courts, Injunctions, Tort, Jurisprudence, Legal theory, etc.

Toppr: a rule of conduct developed by the government or society over a certain territory. Law follows certain practices and customs in order to deal with crime, business, social relationships, property, finance, etc. The Law is controlled and enforced by the controlling authority.

According to Sir John William Salmond (1862–1924), a legal scholar, public servant and judge in New Zealand: (law is) the body of principles recognized and applied by the state in the administration of Justice.

H. L. A. Hart (Herbert Lionel Adolphus Hart; 1907–1992), a British legal philosopher and Professor of Jurisprudence at Oxford University, in his 1961 book The Concept of Law stated that law is a 'system of rules'.

By summarizing the definitions mentioned above, we can say that law is the system of rules which a particular community or country recognizes as the regulating body of the actions of its members and which it may enforce by the imposition of penalties. Also, the word 'law' sometimes refers to any rule that if broken subjects a party to criminal punishment or civil liability.

Having some contextual differences, laws are usually made by federal, state, and local legislatures or members of the parliament, judges, the president, state governors, and administrative agencies.

References

Dennis Lloyd, Baron Lloyd of Hampstead (1975). Introduction to Jurisprudence. Stevens & Sons, London.
Mc Coubrey, Hilaire and White, Nigel D (1996). Textbook on Jurisprudence. Blackstone Press Limited. ISBN: 1-85431-582-X.
Williams, Glanville. International Law and the Controversy Concerning the Meaning of the Word "Law". Revised version published in Laslett (Ed.), Philosophy, Politics and Society (1956).
https://www.collinsdictionary.com
https://www.merriam-webster.com
https://www.britannica.com
https://legal-dictionary.thefreedictionary.com
https://www.lexico.com (Lexico [Oxford English and Spanish Dictionary, Thesaurus, and Spanish to English Translator])
https://www.toppr.com
http://law.uok.edu.in/Files