A more thorough explanation:

Dicta is a legal term that comes from the Latin phrase "obiter dictum," which means "something said in passing." In law, dicta refers to a comment, suggestion, or observation made by a judge in an opinion that is not necessary to resolve the case. Dicta is not legally binding on other courts, but it may still be cited as persuasive authority in future litigation.

For example, in the case of Trump v. Hawaii, Chief Justice John Roberts made a statement that condemned a prior case. This statement was not necessary to resolve the case, but it may still be cited as persuasive authority in future cases.

Dicta can include discussions of hypothetical facts, cases, or laws, or even condemnations of other opinions. Legal scholars sometimes disagree on what constitutes dicta versus statements of binding precedent or authority in a given case.

Despite not being legally binding, dicta is still studied and valued for its potential usefulness. Dicta is frequently incorporated into later opinions and sometimes even serves as the basis of those opinions. For example, in the case of United States v. Carolene Products, Justice Harlan F. Stone made a suggestion in a footnote that eventually served as the basis for the doctrine of strict scrutiny.