violence vs riot

violence and riot both are nouns.

Word	Noun	Adjective	Verb	Adverb
violence	Yes	No	No	No
riot	Yes	No	Yes	No

As nouns, riot is a hyponym of violence; that is, riot is a word with a more specific, narrower meaning than violence:

Other hyponyms of violence include domestic violence, road rage, public violence.

violence (noun)	riot (noun)
an act of aggression (as one against a person who resists)	a public act of violence by an unruly mob
the property of being wild or turbulent	a wild gathering involving excessive drinking and promiscuity
a turbulent state resulting in injuries and destruction etc.	a joke that seems extremely funny
	a state of disorder involving group violence

violence (verb)	riot (verb)
	take part in a riot; disturb the public peace by engaging in a riot
	engage in boisterous, drunken merrymaking