buy vs pick up

buy

verb
  • To obtain (something) in exchange for money or goods. 

  • To make a purchase or purchases, to treat (for a drink, meal or gift) 

  • To make a bluff, usually a large one. 

  • To bribe. 

  • To be equivalent to in value. 

  • To obtain, especially by some sacrifice. 

  • to accept as true; to believe 

noun
  • Something which is bought; a purchase. 

pick up

verb
  • To collect an object, especially in passing. 

  • To acquire (something) accidentally; to catch (a disease). 

  • To collect and detain (a suspect). 

  • To lift; to grasp and raise. 

  • To clean up; to return to an organized state. 

  • To point out the behaviour, habits, or actions of (a person) in a critical manner; used with on. 

  • To meet and seduce somebody for romantic purposes, especially in a social situation. 

  • To receive calls; to function correctly. 

  • To record; to notch up. 

  • To learn, to grasp; to begin to understand; to realize. 

  • To promote somebody who was previously passed over. 

  • To answer a telephone. 

  • To take control (physically) of something. 

  • To mark, to defend against an opposition player by following them closely. 

  • To behave in a manner that results in a foul. 

  • To restart or resume. 

  • To receive (a radio signal or the like). 

  • To notice, detect or discern; to pick up on 

  • To improve, increase, or speed up. 

  • To reduce the despondency of. 

  • To pay for. 

  • To obtain and publish a story, news item, etc. 

  • To collect a passenger. 

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