A lawyer, according to Black's Law Dictionary, is "a person learned in the law; as an attorney, counsel or solicitor; a person who is practicing law." Law is the system of rules of conduct established by the sovereign government of a society to correct wrongs, maintain the stability of political and social authority, and deliver justice. Working as a lawyer involves the practical application of abstract legal theories and knowledge to solve specific individualized problems, or to advance the interests of those who retain (i.e., hire) lawyers to perform legal services.

The role of the lawyer varies significantly across legal jurisdictions, and so it can be treated here in only the most general terms. More information is available in country-specific articles (see below).