starting point vs commencement

starting point and commencement both are nouns.

Word	Noun	Adjective	Verb	Adverb
starting point	Yes	No	No	No
commencement	Yes	No	No	No

As nouns, commencement is a hypernym of starting point; that is, commencement is a word with a broader meaning than starting point:

Other hypernyms of starting point include beginning, first, get-go, kickoff, offset, outset, showtime, start, starting time.

starting point (noun)	commencement (noun)
earliest limiting point	the act of starting something
	an academic exercise in which diplomas are conferred
	the time at which something is supposed to begin