commission vs sign on

commission

verb
  • To put into active service. 

  • To send or officially charge someone or some group to do something. 

  • To place an order for (often a piece of art). 

noun
  • A fee charged by an agent or broker for carrying out a transaction. 

  • The thing to be done as agent for another. 

  • The act of committing (e.g. a crime or error). 

  • A sending or mission (to do or accomplish something). 

  • An official charge or authority to do something, often used of military officers. 

  • A body or group of people, officially tasked with carrying out a particular function. 

sign on

verb
  • To log on; to start using a computer, radio, etc., or to start talking. 

  • To begin broadcasting a radio or television signal, usually at the beginning of a broadcasting day and after being off the air for several hours. 

  • To commit oneself, as to a project, a goal, an organization, a cause. 

  • To join something, after signing. 

  • To apply to receive unemployment benefits. 

noun
  • The time of day when a radio or television station begins broadcasting, usually after being off the air for several hours. 

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