what is the difference between job, occupation, employment and work?
Job and employment are similar. Your "job" consists of the place you go every day to do stuff and they pay you to do it. It is a current regular (usually daily) thing you do. You can call this your employment also. But most people use the word "job". Occupation refers to more of a general kind of work that you do over a period of time, probably you got special training or a college degree to enter this occupation. My job is IT director for a law firm, before that I was IT director for an accounting firm. My occupation is Network Management. Work is a noun or verb: where do you work? means at what company do you have your job right now. I work for a law firm.
I hope this helps.