/əˈdɪʃ(ə)n/

N. a person or thing added or joined, typically in order to improve something.

  • You will find the coat a useful addition to your wardrobe.

N. The addition of something is the fact that it is added to something else.

  • It was completely refurbished in 1987, with the addition of a picnic site.
  • Multiplications and divisions are really just many additions and subtractions.
  • The hotel has been extended with the addition of more rooms.