accessory vs top-up

accessory

noun
  • Something that belongs to part of another main thing; something additional and subordinate, an attachment. 

  • Something in a work of art without being indispensably necessary, for example solely ornamental parts. 

  • An article that completes one's basic outfit, such as a scarf or gloves. 

  • A person who is not present at a crime, but contributes to it as an assistant or instigator. 

adj
  • Having a secondary, supplementary or subordinate function by accompanying as a subordinate; aiding in a secondary way; being additional; contributing or being contributory. Said of things and actions, very rarely of people (and then usually in a humorous version of the legal sense [or due to confusion between the noun and the adjective]). 

  • Assisting a crime without actually participating in committing the crime itself; being connected as an incident or subordinate to a principal. 

  • Present in a minor amount, and not essential. 

top-up

noun
  • An addition. 

  • The situation where a student who holds a qualification equivalent to part of a degree course is then accepted onto a degree course at an intermediate point, without having to start it from the beginning. 

  • Additional credit purchased for a mobile phone. 

  • An additional premium paid over the initial premium in order to increase benefit values. 

  • A serving of drink used to top up an existing glass. 

  • A dose of epidural anesthetic added to previously injected spinal anesthetic in combined spinal-epidural anesthesia 

adj
  • That serves as an addition 

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