com·mence·ment /kəˈmɛnsmənt/ noun plural com·mence·ments
the time when something begins : beginning
— usually + of ▪ They awaited the commencement of the trial. ▪ It's the first attempt at peace since the commencement [=start] of hostilities.
2 US :
a ceremony during which degrees or diplomas are given to students who have graduated from a school or college [noncount
] ▪ the week before commencement [=graduation]
] ▪ A poet will speak at the commencement.
— often used before another noun ▪ a commencement speech/address/ceremony ▪ commencement exercises