Additional is a word that is used to describe something that is added or supplemental to something else. There are several synonyms for the word "additionals" which include: extra, supplementary, further, more, increased, and supplemental. Each of these synonyms conveys the same message as the word "additional" and can be used interchangeably in most contexts. Whether you are referring to an additional cost, an extra feature, or a supplemental resource, there are numerous synonyms available to help you communicate your message more effectively. Consider using these synonyms the next time you are writing or speaking about something that is added or supplemental to something else.