come on

definition: to occur or become available
example:
speech part: verb
synonyms:
definition: to appear or become visible
example:
speech part: verb
synonyms: surface
definition: to start running, functioning, or operating
example: The generators will come on if we lose power.
speech part: verb
synonyms: come up go on
definition: to move towards
example:
speech part: verb
synonyms: approach
definition: to develop in a positive way
example:
speech part: verb
synonyms: progress

How come on is being used?