customer vs sender

customer

noun
  • A native official who exacted customs duties. 

  • A person, especially one engaging in some sort of interaction with others. 

  • A patron, a client; one who purchases or receives a product or service from a business or merchant, or intends to do so. 

sender

noun
  • Someone who sends. 

  • A device or component that transmits, as in telegraphy or computer networks. 

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