Commencement, n.
Etymology: [F. comencement.]
1. The first existence of anything; act or fact of commencing; rise; origin; beginnig; start. The time of Henry VII . . . nearly coincides with the commencement of what is termed "modern history."
2. The day when degrees are conferred by colleges and universities upon students and others.
Shades of meaning
Fernald has no entry of its own for commencement; he lists it under beginning.
Where he writes about it:
The Latin commencement is more formal than the Saxon beginning, as the verb commence, is more formal than begin. — from beginning
Commencement is for the most part restricted to some form of action, while beginning has no restriction, but may be applied to action, state, material, extent, enumeration, or to whatever else may be conceived of as having a first part, point, degree, etc. — from beginning
The letter A is at the beginning (not the commencement) of every alphabet. — from beginning
If we were to speak of the commencement of the Pacific Railroad, we should be understood to refer to the enterprise and its initiatory act; if we were to refer to the roadway we should say "Here is the beginning of the Pacific Railroad." In the great majority of cases begin and beginning are preferable to commence and commencement as the simple, idiomatic English words, always accurate and expressive. — from beginning