additional

The word “additional” means extra; added on top of what already exists. In plain terms, more of something, beyond what was already there.

“Additional” is pronounced uh-DIH-shuh-nuhl (/əˈdɪ.ʃə.nəl/ in IPA).

Here is “additional” used in a sentence: “We need additional staff for the busy season.”

The opposite of “additional” — its antonyms — is nonsupplementary.

“Additional” is an adjective.

The word “additional” comes from Latin. A learned borrowing from Latin additionalis, built from addition plus -al.

“Additional” is a very common word in modern English, usually learned at around the A2 level.

The two are near-synonyms, both meaning added to what already exists. Additional is slightly more formal and neutral, common in writing — 'additional charges may apply.' Extra is more everyday and can also suggest a spare or surplus amount — 'an extra blanket.' In most sentences you can swap one for the other.

If a form asks for 'any additional comments,' it wants remarks beyond what you have already given. 'Additional staff were hired for the holidays' means more workers on top of the usual team. In each case, additional points to something added to an existing amount or set.

There is no single neat antonym, but the opposite idea is something that is included, standard, or original rather than added on. Words like fewer, reduced, or the phrase 'no extra' capture the reverse. Something 'already included' is the counterpart to an additional item that costs or requires more.