When is the official date a degree is obtained? I've read that there is a difference between the date that a higher degree committee approves a student for graduation and the actual date of graduation. The first being the date that a student becomes a graduand and the second being the date that a student becomes a graduate. These two dates could be far apart. My question is which of these two dates should be shown next to a degree on a CV or resume? Obviously I would like it to be the first, but that would lead to a discrepancy between the date on the resume and the date on the certificate. Someone suggested I could show both the completion and graduation date on my CV.
Usually the graduation date is the date on which the last accomplishment needed for graduation was completed.

This could be a thesis defense but could also be something else. For example in some Master and Bachelor programs I know one may have a "final" presentation prior to handing in the thesis. So the graduation date is the date at which the thesis is handed in. Note that even though a thesis defense may not count towards your grade, it is usually still a required accomplishment and consequently it date counts.