agora vs flea market

agora

noun
  • A marketplace, especially in Classical Greece. 

  • Since 1960, a monetary unit and coin of Israel, the 100th part of a shekel / sheqel. 

  • A place for gathering. 

flea market

noun
  • A permanent indoor market of stalls in a warehouse selling inexpensive antiques, outdated goods, curios, etc. 

  • An outdoor temporary market selling inexpensive antiques, curios etc. 

How often have the words agora and flea market occurred in a corpus of books? (source: Google Ngram Viewer )