convention vs indenture

convention

noun
  • A formal agreement, contract, rule, or pact. 

  • A treaty or supplement to such. 

  • A meeting or gathering. 

  • A practice or procedure widely observed in a group, especially to facilitate social interaction; a custom. 

  • The convening of a formal meeting. 

  • A formal deliberative assembly of mandated delegates. 

indenture

noun
  • A contract which binds a person to work for another, under specified conditions, for a specified time (often as an apprentice). 

  • An indentation; a recess. 

  • A document, written as duplicates separated by indentations, specifying such a contract. 

verb
  • To indent; to make hollows, notches, or wrinkles in; to furrow. 

  • To bind a person under such a contract. 

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