Meaning of ADDITIONAL in English
ad ‧ di ‧ tion ‧ al S3 W2 /əˈdɪʃ ə nəl/ BrE AmE adjective
more than what was agreed or expected SYN extra :
Additional information can be obtained from the centre.
additional costs/expenditure etc
An additional charge is made on baggage exceeding the weight allowance.
In everyday English, people usually say extra rather than additional :
He gets extra money from his parents.
• • •
▪ extra in addition to the usual or standard cost, time, amount etc:
They let the kids stay up an extra hour.
Some stores charge extra for delivery.
Postage is extra.
▪ additional [only before noun] more than the basic amount or the amount that you expected or agreed. Additional is more formal than extra :
An evening job would provide additional income.
There may be an additonal charge for paying bills by credit card.
▪ added [only before noun ] extra – used when talking about something that makes something better or more effective:
an added benefit
an added precaution
It was a beautiful place, and the good weather was an added bonus.
Use a sunscreen for added protection.
▪ spare [only before noun] kept in addition to the one you usually use, so that it is available if the one you usually use breaks, gets lost etc:
a spare key
a spare tyre
a spare set of clothes
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012