commencement
n. countable B2 Upper Intermediate US //kəˈmɛnsmənt// UK //kəmˈɛnsmənt// com·mence·ment
n. the formal start of an event, ceremony, or period of time.
n. the formal or official beginning of an event, ceremony, or period; often used in academic or institutional contexts.
The commencement of the project was marked by a speech.
The university held its annual commencement ceremony in the main stadium.
The commencement of hostilities was sudden, catching the diplomatic corps off guard and forcing an immediate recall of ambassadors.
From French commencement; analyzable as commence + -ment.