ad‧di‧tion S3 W1
used to add another piece of information to what you have just said:
The company provides cheap Internet access. In addition, it makes shareware freely available.
in addition to something
In addition to his movie work, Redford is known as a champion of environmental causes.
the act of adding something to something else
the addition of something
The addition of networking facilities will greatly enhance the system.
with the addition of something
Turn sparkling wine into Buck's Fizz with the addition of chilled orange juice.
something that is added to something else, often in order to improve it
the latest addition to our designer range
the process of adding numbers or amounts to make a total [↪ subtraction]
5 [countable] American English
an extra room that is added to a building:
They built a big addition onto the back of the house.