What does initialism mean?
An initialism is an abbreviated expression created from the first letters of a phrase, such as the initials of an organisation, institution, or government department. Its letters are normally pronounced separately: an initialism resembling “A-B-C” is said “A-B-C,” rather than being blended into a new spoken word. This makes initialisms distinct from acronyms, whose letters are generally pronounced as a word, although dictionaries and style guides do not always agree on the distinction. Initialisms are especially common in government, defence, administration, science, and business, where they provide compact references to long names. Once familiar, they may function almost like ordinary words. For unfamiliar readers, however, an initialism can seem opaque because the spoken letters do not immediately reveal the full expression. Writers should introduce an unfamiliar initialism with the complete term and then use the shorter form in subsequent references.
nounAn initialism is an abbreviation formed from the initial letters of the words in a phrase, with each letter normally pronounced separately rather than combined into a spoken word.
- An abbreviation formed from the first letters of the words in a phrase, with the letters usually pronounced individually.
"The department's full name was shortened to an initialism for use in correspondence."
"The agency commonly refers to the Department of Housing and Urban Development by its initialism, HUD."
"Readers unfamiliar with the initialism may need to consult a glossary."
The plural is used when referring to more than one initialism.
"The guide explains several common initialisms used in international aviation."
Initialisms speak in code: every letter announces itself, and the listener must assemble the phrase mentally.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does initialism come from?
Initialism was formed in English by combining initial with the suffix -ism. The word developed alongside the older term acronym, from which it is distinguished chiefly by pronunciation: the letters of an initialism are normally said individually, while the letters of an acronym are normally combined into a word. Both terms reflect the practice of deriving a name or abbreviation from the opening letters of a longer expression.
How initialism is actually used
The distinction between an initialism and an acronym is useful but not applied consistently. Initialisms are especially common in government, defence, science, and business.
Easily confused with initialism
An initialism is normally pronounced letter by letter, whereas an acronym is normally pronounced as a single word, although some usage guides treat the terms as interchangeable.