Twentyfifth
Twentyfifth is the ordinal form used to identify the position of twenty-five in a sequence. In standard English, ordinals from twenty to twenty-nine are written with a hyphen: twenty-fifth, twenty-sixth, twenty-seventh, and so on, and numerically as 25th. The non-hyphenated form “twentyfifth” is uncommon and typically found only in contexts that require no spaces or punctuation, such as certain filenames, identifiers, or stylistic choices.
The term is formed by combining the cardinal twenty with the ordinal fifth, using the ordinary English
See also: ordinal numbers, twenty-fourth, twenty-sixth, and related calendrical and historical uses.