spelledout

Spelledout is a term used to describe the representation of items in words rather than numerals or symbols. In writing and typography, spelled-out forms convey numbers, dates, and terms using words instead of digits. Spelled-out numbers are common in formal prose, while digits are preferred for precise data, dates, times, currency, and large quantities. Style guides often advise spelling out numbers under a certain threshold and using digits for measurements and larger numerals; the exact rules vary by guide and context. Compound numbers that function as adjectives typically require hyphenation, such as twenty-one or ninety-nine. Numbers beginning a sentence are usually spelled out.

Spelled-out forms also apply to acronyms and initialisms. On first mention, many writers spell out the full phrase before introducing the abbreviation, for example, the National Aeronautics and Space Administration (NASA). This practice helps clarity in formal writing.

In computing and natural language processing, spelled-out describes the process of converting numeric or symbolic input into its word representation, for example 123 becomes "one hundred twenty-three." Several programming libraries and language tools implement this transformation, with language-specific rules for hyphenation and grammar.

The term is also used in lexicographic or localization contexts to describe tokens that are explicitly written in words, as opposed to numerals or symbols. Spelledout thus sits at the intersection of typography, style, and natural language processing, guiding how numbers and abbreviations are presented in text.