Hi Lucy, Good question. For me, these words represent different modes; different aspects of the the world of employment (mostly). 'Career' implies planned direction of travel over time, perhaps notionally from completing initial training to retirement and everything relatable in between. 'Occupation' nominally refers to the field of activity: In my case, Teacher-Mentor-Educator. Or, engineer, soldier artist. 'Job' often describes the day to day functionality, and can be quite specific: Taxi driver, principal volinist, data analyst, online educator. Alternatively, job can also denote a specific piece of work: ''I finished the job I needed to do.'' Others may see a different perspective.

Many people have just one career in an entire lifetime. If you change careers, it means you start to do something totally different. For example, if you change from being a taxi driver to being a car mechanic that would be a "change of career". "Occupation" is how you spend your time. It need not be related to any job or career. It could even be a hobby. For example, a photographer might say his occupation is taking pictures of hawks, even though he loses money doing that. It just means that that is how he spends most of his time. Most people, however, do not have the luxury of spending their time in such a beautiful way. They need to make money. Occupations like medicine, trash collection, restaurant management, law, teaching, and so forth, allow one to earn money. Occupations are not jobs though. Medicine is not a job. Medicine is a category of human endeavor. You can have a job IN medicine, like being a doctor or nurse, but medicine itself is a category, not a job. A "job" is usually an agreement between one specific employer and one specific employee. But it's more than that. Any task to which you feel duty bound can be considered a "job", whether or not there is an employer. For example, you can say "Sorry I cannot go hiking with you. I have a big job to do at home. I need to pull the weeds in my yard."

I would say "Teacher Gary" has summed it up very nicely. Nothing more to add.

Just how formal they are