It's the work you spend the most time doing and, usually, get paid to do. There are exceptions to the getting paid to do definition, like "student" and "housewife" or "home maker" or "retired."
You can think of it like the answer to the question you might ask some one: "What do you do for a living?" But many people have more than one job, so they have to chose the one they do most often.
People's usual occupations will vary. Your occupation is generally what you do for work and how you make a living. Some people, for instance, might be teachers; others might be shopkeepers.
The opposite, or alternative, to usual job would be called a sideline or side job.*The word avocation is often used as its own opposite, to mean either a job outside of usual work, or to mean one's usual occupation, as in vocation. Only the context would tell you which meaning it intends.
What does that mean? -Monaco is country, it does not have an "occupation"
What you are currently working as. Your occupation as in your job or profession.
They were able to get back to their usual occupation of fighting each other.
your occupation
choosing a profession
They were no longer threatened by Persia and could get back to their usual occupation of fighting each other.
Synonyms for usual might be normal, commonplace, standard.
the job of your husband or wife. occupation = job spouse= the person you're married to
usual
What it means to give out a usual speech is that one presents a speech in the usual manner. There is nothing out of the ordinary when the speech is given out.