riot vs violence

riot and violence both are nouns.

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

As nouns, violence is a hypernym of riot; that is, violence is a word with a broader meaning than riot:

Other hypernyms of riot include force.

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

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