Origin: Latin suffix -al
Additional has 3 different meanings across 1 category:
Something added.
"She asked for an additional cup of coffee to go along with her breakfast."
In plain English: An additional is an extra item that comes on top of what you already have.
"The additional was clearly marked on the receipt."
Usage: Additional is strictly an adjective and should never be used as a noun to mean "something added." Instead, use countable nouns like "item," "amount," or specific terms such as "supplement" or "addition."
further or added
"called for additional troops"
"need extra help"
"an extra pair of shoes"
Supplemental or added to something.
"We need additional funds to cover the unexpected repair costs for the roof."
In plain English: Additional means something extra that is added to what you already have.
"She decided to order an additional slice of pizza for everyone to share."
Usage: Use additional to describe extra items or quantities that are added to an existing amount. It typically functions as an adjective placed directly before a noun to indicate supplementation.
The word additional comes from combining the noun addition with the suffix -al to mean something added on. It entered English directly through this straightforward formation rather than borrowing a foreign root.