It is an unsettled question in English lexicography and style guides whether it is legitimate to use the word "acronym" to describe forms that use initials but are not pronounced as a word. While there is plenty of evidence that "acronym" is used widely in this way, some sources do not acknowledge this usage, reserving the term "acronym" only for forms pronounced as a word, and using "initialism" or "abbreviation" for those that are not. Some sources acknowledge the usage, but vary in whether they criticize or forbid it, allow it without comment, or explicitly advocate for it.