Commencement/kəˈmensmənt/ Definition 1 of 3Pro Tip 1/3Starting Point Use 'commencement' to talk about the exact time when something new begins. The commencement of the festival is at noon. Pro Tip 2/3Momentous Occasions 'Commencement' often implies an important or formal beginning of a significant event. The commencement of peace talks was a historic event. Pro Tip 3/3Not for Routines Avoid using 'commencement' for routine starts or non-significant beginnings. We don't say 'commencement of breakfast' for a daily routine.