ASCII files are files that store plain text and use a standard set of characters. There are several synonyms for ASCII files that are commonly used in the computing industry. One such synonym is "text files," which also refers to files composed of plain text. Another synonym for ASCII files is "unformatted files," as ASCII files do not include any formatting such as bold or italic text. "Plain-text files" is another term for ASCII files that emphasizes the absence of any formatting. Finally, "ASCII text files" is a synonym that specifically highlights the use of the ASCII character set to represent the text within the file.