This is when the interviewer has a number of questions written on some paper, and you ask him those questions and note them down word for word. The questions are normally made before the interview, and the other times they are handed to the interviewer by the human resources department. They prefer the structured interviews and take time out for every particular interview. Some interviewers use a general script that has been cleared by the human resources.
It is where there might be a script to start things off, but after some time the interviewer will shift to his favourite topics and discard the script given to him. You will note that a few managers use unstructured interviews while conducting business. This is because it helps in analysing a problem that might not have been mentioned in an application or resume but it important with respect to the job.