As a Noun: 1. A large crowd of people or animals backed up in long queues. 2. Long lines of cars backed up on a multi-lane road. English = traffic jam. 3. Multiple lanes for cars on a wide road. English = traffic lanes. As a Verb or Adjective: 1. Of a large crowd of people or animals, to be backed up in long queues. 2. Of long lines of cars, to be backed up on a multi-lane road.