what are Jim Crow laws?

from answers.com

After 1877, the Redeemers reversed many of the civil rights gains that black Americans had made during Reconstruction, passing laws that mandated discrimination by both local governments and by private citizens. Since "Jim Crow law" is a blanket term for any of this type of legislation, the exact date of inception for the laws varies by state. The most important laws came in the 1890s and the adoption of legislation segregating railroad cars in New Orleans as the first genuine Jim Crow law. By 1915, every Southern state had effectively destroyed the gains in civil rights and liberties that blacks had enjoyed due to the Reconstructionist efforts.

It is thought that the term 'Jim Crow laws' originated from the 1828 popular song Jump Jim Crow, a blackface song which made derogatory references to the character of colored people. As a result of this song, the term 'Jim Crow' became a pejorative or mocking term for colored people, used in the Deep South.

Between 1890 and 1920, many state governments prevented most blacks from voting by various techniques, such as poll taxes and literacy tests. (These could be waived for whites due to grandfather clauses.) It is estimated that of 181,000 African-American males of voting age in Alabama in 1900, only 3,000 were registered to vote.

Many of the discriminatory Jim Crow laws were enacted to support racial segregation in everyday life. They required black and white people to use separate water fountains, public schools, public bath houses, restaurants, public libraries, buses and rail cars -- although, even without legal segregation, the desire of the white majority to use the frequently inferior facilities set aside for black use was admittedly limited.