a) The first existence of anything; act or fact of commencing; rise; origin; beginning; start.
The time of Henry VII ... nearly coincides with the commencement of what is termed modern history. -allam.
b) The day when degrees are conferred by colleges and universities upon students and others.
1800, William Took, View of the Russian empire during the reign of Catharine the Second
See Also: commence
Wikipedia foundation.