start vs commence

start is a noun but commence is not a noun.

Word	Noun	Adjective	Verb	Adverb
start	Yes	No	Yes	No
commence	No	No	Yes	No

As verbs, start and commence are synonyms defined as:

start and commence: take the first step or steps in carrying out an action

Other synonyms of start include begin, get, get down, set about, set out, start out.

As verbs, start and commence are synonyms defined as:

Other synonyms of start include begin, lead off.

As verbs, commence is a hyponym of start; that is, commence is a word with a more specific, narrower meaning than start:

As verbs, start and commence are synonyms defined as:

Other synonyms of start include embark on, start up.

As verbs, commence is a hypernym of start; that is, commence is a word with a broader meaning than start:

Other hypernyms of start include begin, lead off, start.

start (noun)	commence (noun)
the act of starting something
a sudden involuntary movement
a turn to be a starter (in a game at the beginning)
the advantage gained by beginning early (as in a race)
a signal to begin (as in a race)
the beginning of anything
a line indicating the location of the start of a race or a game
the time at which something is supposed to begin

start (verb)	commence (verb)
take the first step or steps in carrying out an action	take the first step or steps in carrying out an action
set in motion, cause to start	set in motion, cause to start
play in the starting lineup	get off the ground
bring into being
get off the ground
begin or set in motion
get going or set in motion
depart for someplace
bulge outward
move or jump suddenly, as if in surprise or alarm
begin work or acting in a certain capacity, office or job
begin an event that is implied and limited by the nature or inherent function of the direct object
have a beginning, in a temporal, spatial, or evaluative sense
have a beginning characterized in some specified way