An Event is the main parent of the market, there are no orphan markets.
They are associated to a Match or a general category in case of special event ( Bitcoin, Weather, Politics, etc..), on the other hand, markets are the specific subcategory of the event, where users are allowed to place the bets ( related to the main parent - event).
Any given event, such as a soccer match, may have a number of different markets: for example, Match Odds, Over/Under Goas/, Extra Time, etc... This is the place to view the odds and have a bet.
Example: Event - Soccer Match Real Madrid vs Barcelona Market - "Match Odds" "Over/Under 2.5 goals"