Hello,

In the Category Setup screen is a field called "URL Keywords". The keywords entered in this field will be dynamically added in the URL of the product listing page when a user clicks on a category from the categories module. Enter keywords that are relevant and targeted towards your category. Targeted keywords in the URL help your SEO rankings. If you enter several keywords use hyphens as dividers and not underscores as hyphens have proven better for SEO.

Hope this helps!