Each opinion has a title. It is usually identified by the reporter where it is reported.
For example, Brown v. Board of Education (I) is the title of the Supreme Court case that covered ten appeals, one of which being the Kansas case against the Board of Education of Topeka.
In the Kansas case, Brown v. Board of Education, the plaintiffs are what the court identifies them, Negro children of elementary school age—“minors of the Negro race”—who reside in Topeka. They brought this action in the U.S.District Court for the District of Kansas to enjoin enforcement of a Kansas statute that permits, but does not require, cities of more than 15,000 population to maintain separate school facilities for Negro and white students.
It is standard practice that the title of a case consists of the last name of the individual plaintiff and the last name of the individual defendant, or an abbreviation of their corporate names separated by the abbreviation “v.” for the Latin word “versus,” which means “against.” The title of the case is always followed by the location of the opinion: the abbreviation of the compilation of opinions preceded by the volume of that compilation and followed by the page number where the opinion starts. At the end, more information regarding the year of the decision is usually added.
Thus, the full citation for Brown v. Board of Education (I) is Brown v. Board of Education (I), 347 U.S. 483 (1954).
As you might suspect, this means that the full opinion in Brown can be found in the 347th volume of the United States Reports, and it starts at page 483. The opinion was decided by the U.S. Supreme Court in 1954. As explained earlier, because the U.S. Supreme Court opinions can be found a quite a few print and online repositories, the citation presented above is only one of the many such citations.