Undergraduate - Bachelor's degree Graduate -- Master's degree Postgraduate - Doctorate, Phd

Sorry just noticed second part of your question. It is correct to say that you have a Diploma in your subject ie. Dip.Hum is a diploma in Humanities. Dip.Mus is a diploma in Music. Normally those working towards a Batchelors degree would in perhaps the second year have the necessary qualifications to apply for the Diploma. I know that with the Open University it is possible to use credits for two qualifications. Good luck with your studies.

Hi Nicole was almost there: Undergraduate as the prefix under denotes has not yet qualified they will be working towards a degree. Graduate has obtained a degree BA, BSc, etc. Postgraduate, again post means after, that would be the next level masters, Doctorate etc. Hope this helps. Tony.

As a native U.S. speaker, I would say these things, in this way, using this phrasing: a) I am a college graduate. (That is, I went to a university for four years, and didn't flunk out). b) I have a bachelor's degree from [X university]. c) I went on to grad school at [Y university]. d) My undergraduate degree from X was in Z. OR, I majored in Z at X]. e) My graduate degree is in Q. OR, I got [a master's degree/a doctor's degree/a Ph.D.] in Q. I wouldn't actually use the term "postgraduate." I see "postgraduate" mostly on questionnaires where I am being asked to indicate how much and what kind of education I've had. I can imagine this dialog: "Have you had any postgraduate education?" "Yes, I got a graduate degree from the University of Winnemac, it was a master's in Q..."