Vocational courses are ones that relate to a vocation/job/what someone is qualified to do. So if you degree is vocational it directly relates to a type of occupation Of course, non-vocational courses would relate more to courses which don't necessarily link to a specific occupation. For example: sociology.

search google "define: vocational " --> directed for a particular employment or skills for example lawyer or plumber.

I believe vocational courses have to do with a specific job. In other words, courses that provide skills for a particular specialization. As for non-vocational, well, that's relatively obvious: courses that do not provide anything for skills of a particular trade. If it were up to me guessing the difference, I'd say it's similar to electives outside of a degree (ex: Chinese taken while being a major of a technology degree would be considered non-vocational).