What does "turnout" mean? Is it a ratio?

Native speaker’s answer
Rebecca
"Turnout" is a noun meaning the number of people that participate in an event or occasion. It is most commonly associated with voting. Ex: Voter turnout has not been high for the past few elections. It seems many people are becoming ambivalent about politics. Ex: The turnout for the event was not bad. Over 80% of people who RSVPed ended up attending.