She has work but he doesn’t have a job.

She has work but he doesn’t have a job.

means

She has a job but he doesn’t have work.

Count Noun

“Job” is a count noun so it needs an article:

He has a job

Non-Count Noun

“Work” is a non-count noun so it does not have an article:

She has work.

Parallel Phrases

Both of these phrases are the same.

Are you looking for work?
Are you looking for a job?

Note that one noun (job) has the indefinite article “a” but the other one (work) does not.

Common Mistakes

He has job.

She has a work.

We don’t say the above sentences because the grammar is wrong.

Count Nouns and Non-Count Nouns

Things which can be counted:

dogs, cats, people, jobs, bottles

a dog, a cat, a person, a job, a bottle

Things which can not be counted:

milk, sugar, liquid, rice, work

some milk, some sugar, some liquid, some rice, some work

Confusion

Sometimes people get confused because we say:

Can I have a beer please?

Can I have a coffee please?

Can I have a water please?

These phrases actually mean:

Can I have a glass of beer, please?

Can I have a cup of coffee, please?

Can I have a glass of beer, please?

The Difference between Work and a Job

Although they mean the same thing, in practice, we use “work” differently.

Look at these examples:

Job

When did you start your job?

This means:

“On what date did you start working for this employer in this particular job?”

You could answer:

I started my job in March 2015 so I have been working in that job for about two and a half years.

Work

When do you start work?

This means:

At what time do you start work on any particular day?

You might answer:

I start work at seven thirty in the morning and I work until about three or four pm in the afternoon.

Going to Work

We generally say:

I go to work at seven.

We don’t say:

I go to job

We generally say:

What time do you start work?
What time do you go to work?
What days do you work?

But we say:

I have a job.

Question

Do you have a job?

Tell us about it in the comments section below:

“Work” and “employment” are general non-count nouns.

Read about how they are used at this link:
Work and Employment

Job is s specific count noun.

Links

Links to More Lessons: Vocabulary

The Future of Work and Employment