What does rush hour mean?

Very easy question ... It's a time during each day when traffic is at its heaviest. Usually in the morning and evening. In the mornings it occurs when people are trying to get to school or work (Usually in a rush so there's a lot of traffic). In the evenings (3P. M.-6P. M.) occurs when people are getting out of work and students are getting out of school, obviously wanting to go home.