Learn English – What’s the difference between Start time and Starting time

There's room for flexibility here, but job duties sounds like a list of duties that come with the job. It's a list of what the employee is expected to do:

• Clean tables
• Buy food
• Take orders

On the other hand, job description sounds more like a description of the job, which would include the job duties, but often goes beyond the duties; for example:

• Must be at least 17 years old
• Must be willing to work until 10PM on weekends
• Must have a valid driver's license

(These aren't duties, because they aren't things that the employee would do.)

So, job duties are part of a job description, but job descriptions often include both duties and qualifications. Like I said, though, there is plenty of wiggle room. For example, I've also heard position description used in place of job description.

Satisfy has these two Latin words as a root (from Google):

late Middle English: from Old French satisfier, formed irregularly from Latin satisfacere ‘to content,’ from satis ‘enough’ + facere ‘make.’

whereas fulfill has this etymology:

late Old English fullfyllan ‘fill up, make full’ (see full1, fill).

When something is full, putting more in will make it overflow.

So satisfy implies that there is a minimum to consider good, but you could do more to improve things further than the minimum.

Fulfill implies that either you achieved a standard (reached the "full" line") or did not. There is really no such thing as "halfway fulfilled," for example.

This is why things like destinies or orders are fulfilled, but not satisfied. Either you reached your destiny or you didn't, either your order is complete or it is not. But you could satisfy an indignant customer who didn't get an order fulfilled by giving him/her a gift card, though a higher amount gift card would make him/her more satisfied.