What is an 'instructor' and how do they differ from professors?

What is an 'instructor' and how do they differ from professors?

Professors are employees of the institution, meaning that they are long term employees who are in charge of designing the curriculum as well as making sure that the curriculum is up to date. Instructors are temporary employees who are hired on a semester or yearly basis to assist the faculty to teach the courses. So many times when there are a lot of people who want to take a particular course and there are more students who are interested in taking the course than there are professors to teach it, instructors are hired to teach the class that particular year to be able to accommodate for the need.