charge up vs piggyback

charge up

verb
  • To motivate, to instill someone with determination. 

  • To recharge, to give electrical power to something. 

  • To deliberately infect an individual with HIV as part of bug-chasing. 

piggyback

verb
  • To carry (someone) on the back or shoulders. 

  • To transport (a lorry/truck) on a flatbed railway waggon 

  • To utilize "last-mile" wiring rented from a larger owner ISP by a smaller ISP. 

  • To obtain a wireless internet connection by bringing one's own computer within the range of another's wireless connection without that subscriber's permission or knowledge. 

  • To enter a secured area at the same time along with someone having authorized access; to tailgate 

  • To attach or append something to another (usually larger) object or event. 

adv
  • On somebody's back or shoulders. 

adj
  • On somebody's back or shoulders. 

  • Pertaining to transportation of goods where one transportation unit is carried on the back of something else. For example, a truck on a train. 

  • Attached or appended to something larger or more important. 

noun
  • An act or instance of piggybacking. 

  • The connection of one intravenous drip to another. 

  • A ride on somebody's back or shoulders. 

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