A more thorough explanation:

Definition: Black codes were laws enacted in the United States during the antebellum period to regulate slavery and, after the Civil War, in the ex-Confederate states to restrict the liberties of newly freed slaves to ensure a supply of inexpensive agricultural labor and to maintain white supremacy.

For example, after the Civil War, many southern states passed black codes that made it illegal for African Americans to vote, serve on juries, or own guns. These laws were meant to keep African Americans in a lower social and economic position than white people.

The black codes illustrate how laws can be used to oppress and discriminate against certain groups of people. They also show how difficult it can be to achieve true equality and justice, even after major social and political changes like the end of slavery.