customer service vs serving

customer service

noun
  • The act of providing services to customers before, during and after a purchase. 

  • A department that provides services to existing customers. 

serving

noun
  • The act or process of serving. 

  • A layer added to the outside of an electrical cable to protect it. 

  • An instance of that act or process; also (usually, especially) the amount of food or drink for or served to one person; especially in relation to a meal. 

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