21st
|twen-ty-first|
🇺🇸
/ˌtwɛntiˈfɝst/
🇬🇧
/ˌtwɛntiˈfɜːst/
21st position
Etymology
'21st' is a numeric orthographic form combining the cardinal element '21' (from 'twenty-one') with the ordinal suffix 'st' (an abbreviation of 'first'). 'Twenty' ultimately comes from Old English 'twentig' and 'one' from Old English 'an'; 'first' comes from Old English 'fyrst'.
'twenty-one' developed from Old English components ('twentig' + 'an') into the modern spoken and written 'twenty-one'. The written shorthand '21st' arose by attaching the ordinal marker 'st' (from 'first') to the numeral '21'.
Initially the elements meant simply 'two tens and one' and 'first' in Old English; over time they combined into the modern ordinal used to mark the 21st position, a meaning that has remained stable.
Meanings by Part of Speech
Noun 1
a shorthand reference to the 21st instance of something (often a day or year), e.g., 'the 21st' meaning the 21st day of a month or the 21st year/century.
Her birthday is the 21st.
Synonyms
Adjective 1
used before a noun to mark that noun as being in the 21st position (e.g., the 21st century).
The 21st century has seen rapid technological change.
Synonyms
Numeral 1
an ordinal number indicating the position 21 in a sequence; 'twenty-first'.
My office is on the 21st floor.
Synonyms
Idioms
Last updated: 2025/12/18 21:51