The URL key field in Magento is a great tool for SEO purposes when it reflects the name of your product as it appears on the website. To ensure that you are taking advantage of this, always edit the name of the product the very first time you open it. When a new product is imported into Magento, the URL key field is blank. The first time the new product is opened and saved, whatever info is in the name field is copied down to the URL key field. So, if a description is entered but the name is not changed, the URL key will reflect the name that came over from your POS system. If you go in later and edit the name, the URL key field will not change. You don't want that field changing all the time, so Magento does not update that field.
To avoid this, always edit the name field the first time you open a new product in Magento to whatever you want it to be on the website. That way the URL key field will be correct.