Initialism

An initialism is an abbreviation formed by using the first letters, or initials, of a series of words, for example BBC, IBM, or NATO. The term initialism is often used by those who prefer to define an acronym as an abbreviation whose letters form a pronounceable word, like NATO or AIDS. "Initialism" is then the name of the category for abbreviations that don't meet the strict definition of acronym and are pronounced as a series of the names of the constituent letters.

See also: List of initialisms and List of general acronyms