What is the difference between "termination pay", "notice" and "severance"?

These terms are often confused. In ordinary conversation termination pay and severance pay are the same things. However, legally speaking, when an employee is fired they are often entitled to both:

advanced “notice” of termination (or “termination pay” instead of notice); and
a lump sum pay based on their years of service which is referred to in the Employment Standards Act as “severance”.