A more thorough explanation:

A dissenting opinion is a written opinion by a judge who disagrees with the majority opinion in a court case. This means that the judge has a different view on the legal issue being decided. The judge who writes a dissenting opinion is said to dissent.

Dissenting opinions are not binding law, which means that future cases are not required to follow them. However, they are important because they preserve minority viewpoints on contested legal issues and contribute to the public debate of these issues. In some rare cases, the views expressed in a dissenting opinion may be adopted as law in future court cases or encourage legislation overriding the majority opinion.

For example, in the case of Katz v. United States, the Supreme Court adopted the dissenting views of Olmstead v. United States when they held that wiretapping infringes upon the Fourth Amendment right against unreasonable searches and seizures. This means that the dissenting opinion in Olmstead became the majority opinion in Katz.

Another example is the case of Plessy v. Ferguson, where the Supreme Court upheld racial segregation in public facilities. Justice John Marshall Harlan wrote a famous dissenting opinion, arguing that "our Constitution is color-blind, and neither knows nor tolerates classes among citizens." This dissenting opinion became influential in the civil rights movement and eventually led to the landmark decision of Brown v. Board of Education, which declared segregation unconstitutional.