Hi Yama, hi Sara,
Thanks Yama for alternative - would you say this is more American usage? We tend more to use "Graduation" in the UK. As well as being useful to me as a translator, I think it's a good point to have British/American English alternatives in the fourm.
I found another link: http://www.answers.com/topic/commencement
Commencement is, following this line of thought, a kind of inauguration - the culmination of studies which marks the beginning of life as a graduate?
Cheers and happy commencement / graduation