client vs purchaser

client

noun
  • A customer, a buyer or receiver of goods or services. 

  • The role of a computer application or system that requests and/or consumes the services provided by another having the role of server. 

  • A person who receives help or services from a professional such as a lawyer or accountant. 

  • A person who employs or retains an attorney to represent him or her in any legal matter, or one who merely divulges confidential matters to an attorney while pursuing professional assistance without subsequently retaining the attorney. 

purchaser

noun
  • One who purchases. 

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