begin vs come on

begin and come on both are verbs.

Word	Noun	Adjective	Verb	Adverb
begin	No	No	Yes	No
come on	No	No	Yes	No

As verbs, come on is a hyponym of begin; that is, come on is a word with a more specific, narrower meaning than begin:

begin (verb)	come on (verb)
take the first step or steps in carrying out an action	occur or become available
set in motion, cause to start	appear or become visible; make a showing
begin to speak or say	develop in a positive way
begin to speak, understand, read, and write a language	start running, functioning, or operating
achieve or accomplish in the least degree, usually used in the negative	move towards
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
be the first item or point, constitute the beginning or start, come first in a series
have a beginning characterized in some specified way
have a beginning, of a temporal event