The word "21st" is correct and usable in written English.
It typically refers to the 21st day or the 21st century, and can be used in both formal and informal writing. For example, "on the 21st of October, the president made an address to the nation".
In the 21st century but 21st-century boy; fourth century BC; AD2007, 2500BC, 10,000BC.
Session 24: Final readings and course review - Monday 21st March Five students read 1000 words of their final assessment piece.
Anthony Stokes looked to have put the visitors on course for a 21st consecutive victory in domestic competitions when he scored after 28 minutes.
See, for example, Fisa for the 21st Century, Hearing Before the S. Comm. on the Judiciary, 109th Cong.
Related: Dundee 0-1 Inverness | Scottish Premiership match report In the case of Inverness, in the year of their 21st birthday, this flagship occasion and opportunity to claim what would be a first piece of major silverware could hardly be more timely.
There is some discussion of what Labour should be saying about Britain in the 21st century, which is half of the right question.
Paper Tiles, £22/m Charlotte Abrahams' exhibition, Pasting The Walls: A Celebration Of 21st-Century Wallpaper, is at the Select Festival from 29 April-31 May.
To precede the section concerned with the wholly disarming George, the 21st-century 15-year-old, Wood made an image of a CCTV camera.
Many of the book's 700 pages are spent marshalling the evidence that 21st-century capitalism is on a one-way journey towards inequality – unless we do something.
The TPP, sure to make an appearance during tonight's State of the Union, is a 21st-century trade agreement involving 11 Asian countries along the Pacific Rim, and said to cover 40% of the world's economy.
They have until the end of the month to make the service appropriate to 21st-century Britain.
