To further muddy the waters - It varies from country to country too.
here in Ireland there's a Higher Education heirarchy -
Higher Certificate is at level 6
Ordinary Degree and (almost defunct) National Diploma = level 7
Hons Degree and Higher Diploma = level 8
Masters Degree = Level 9
Doctoral Degree = level 10
This is apparently based on European and UN guidelines to allow the transport of qualifications from country to country.
http://www.nfq.ie/nfq/en/documents/determinati ons.pdf