A more thorough explanation:

v.

An abbreviation for "versus," which means "against." It is used in case names to show the two parties that are in a legal dispute.

• Brown v. Board of Education
• United States v. Nixon
• Smith v. Jones

These examples show how the "v." is used to indicate the two parties that are in a legal dispute. In Brown v. Board of Education, the case was about segregation in schools. In United States v. Nixon, the case was about the Watergate scandal. And in Smith v. Jones, the case could be about anything where two people or entities are in a legal dispute.

Adverse party