A job is an activity that involves some sort of work, and the person who does the work is often paid. Many people go to a job every day. The words "job" and "work" are similar, but they aren’t used in exactly the same ways.
The word "job" is almost always a noun. In these sentences, it’s a place of employment:
Darryl has a good job. He works as an engineer.
Theresa has to travel 45 minutes every day to get to her job.
Bill is looking for a job. He’s been out of work for three months.
What kind of a job is he looking for?
He has an interesting job.
You will also hear Americans use the noun "job" for an accomplishment or for good effort.
She did a good job on her assignment.
The teacher wrote "good job!" on the top of Matthew’s essay.
"Good job," said the mother of the child who finished eating all of his vegetables. ("Good job," is a common expression among parents who praise their children for doing something well, such as eating all of one’s food, cleaning one’s bedroom, getting dressed, etc.)
Members of the military who engage in combat or missions may refer to their activities as a job:
The soldiers fighting in Afghanistan hope to successfully finish the job and come home soon.
It was a difficult job to win the hearts and minds of the people in Baghdad.
Members of the infantry (foot soldiers) have a very dangerous job to do.
It’s also possible to use the word "job" as an adjective:
He did a job search online.
There’s a job opening in the sales department.
Job seekers flooded the company with applications.
Quality is job one. (This is popular expression. To say that something is "job one" means that aspect of the work receives high priority. It’s very important.)