words is a standard file on all Unix and Unix-like operating systems, and is simply a newline delimited list of dictionary words. It is used, for instance, by spell checking programs.

With Unix's text processing capabilities, one can use the words file for many purposes. For example, using the grep tool, one can find all three letter words without any vowels, using regular expressions: egrep -i "^[^aeiou']{3}$" /usr/share/dict/words

The words file is usually stored in /usr/share/dict/words, or /usr/share/words. On the Mac OS X system, the file path is /usr/share/dict/words.

On Ubuntu, the words file is provided by the wordlist package, or its Provider packages wbritish, wamerican, etc.

A words file is also used to contain words related to a specific topic. One such example of this is for profanity censoring software that replaces profanities, for example, posted on the web with strings such as "###" or some other replacement. Words that are posted in this example are compared with a "bad-words" file and then if there is an occurrence of such a word, it is summarily replaced.