Another way we define "career" is as a series of jobs an individual has over his or her lifetime. These jobs may reflect an upward trajectory meaning that one will have increasing responsibilities, compensation and more prestigious titles with each subsequent position. Alternatively, none of this may be true. Some people's careers are filled with unrelated jobs, or an individual may not experience upward progression, but instead may stay at the same level throughout his or her entire working life.
These multiple, yet related meanings, might confuse you a bit since your career (series of jobs) could consist of several different careers (occupations). For example: "Mark began his career as a carpenter. He went back to school to become a project manager and eventually decided to follow his childhood dream and became an actor."