bastion vs protection

bastion

noun
  • A well-fortified position; a stronghold or citadel. 

  • A person, group, or thing, that strongly defends some principle. 

  • A projecting part of a rampart or other fortification. 

  • Any large prominence; something that resembles a bastion in size and form. 

verb
  • To furnish with a bastion. 

protection

noun
  • A means of keeping or remaining safe. 

  • Coverage. 

  • The process of keeping (something or someone) safe. 

  • The state of being safe. 

  • An instance of a security token associated with a resource (such as a file). 

  • Restrictions on foreign competitors which limit their ability to compete with domestic producers of goods or services. 

  • A means, such as a condom, of preventing pregnancy or sexually transmitted disease. 

  • Immunity from harm, obtained by illegal payments, as bribery or extortion. 

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