( Rossum's Universal Robots ) ( 1921 ) – the play that introduced the word robot to the world – were organic artificial humans, the word " robot " has come to primarily refer to mechanical humans, animals, and other beings.

* 1921 – Robert Cliche, Canadian politician and magistrate ( d. 1978 )

* 1921 – Black Friday: mine owners announce more wage and price cuts, leading to the threat of a strike all across England.

* 1921 – Tove Maës, Danish actress ( d. 2011 )

* 1921 – Georg Alexander, Duke of Mecklenburg ( d. 1996 )

* 1921 – Leo Penn, American director ( d. 1998 )

* 1921 – Ernest Angley, American evangelist and broadcaster

* 1921 – J. James Exon, American politician ( d. 2005 )

They won the first eight matches in succession including a 5 – 0 whitewash in 1920 – 1921 at the hands of Warwick Armstrong's team.

* 2008 – Jake Warren, Canadian diplomat ( b. 1921 )

* 2012 – N. K. P. Salve, Indian politician ( b. 1921 )

The most important Canadian theorist was an American immigrant, Henry Wise Wood, president of the United Farmers of Alberta ( UFA ) during that movement's time as the governing party of the province ( 1921 – 1935 ).

* 1921 – Jack Kramer, American tennis player ( d. 2009 )

* 1921 – Major League Baseball Commissioner Kenesaw Mountain Landis confirms the ban of the eight Chicago Black Sox, the day after they were acquitted by a Chicago court.

* 1921 – Marilyn Maxwell, American actress ( d. 1972 )

* 1921 – Richard Adler, American songwriter and composer ( d. 2012 )

* 1921 – Hayden Carruth, American poet and critic ( d. 2008 )

* 1999 – Byron Farwell, American historian ( b. 1921 )

The second generation was led by Fernand Braudel ( 1902 – 1985 ) and included Georges Duby ( 1919 – 1996 ), Pierre Goubert ( 1915 – 2012 ), Robert Mandrou ( 1921 – 1984 ), Pierre Chaunu ( 1923 – 2009 ), Jacques Le Goff ( 1924 – ) and Ernest Labrousse ( 1895 – 1988 ).

* In 1921, the British were the first to cross the North Atlantic in an airship.

* 1921 – British airship R-38 experiences structural failure over Hull in England and crashes in the Humber estuary.

Similarly, the language spread to numerous other parts of the world as a result of British trade and colonization elsewhere and the spread of the former British Empire, which, by 1921, held sway over a population of 470 – 570 million people, approximately a quarter of the world's population at that time.

* 1921 – Emir Abdullah establishes the first centralised government in the newly created British protectorate of Transjordan.

* 2003 – David Greene, British director ( b. 1921 )

In January 1921, the British Labour Commission produced a report on the situation in Ireland which was highly critical of the government's security policy.

* 1921 – Bob Todd, British comedian ( d. 1992 )

* 1921 – The Anglo-Irish Treaty is signed in London by British and Irish representatives.

* 1921 – Liz Smith, British actress

Donald Malcolm Campbell, CBE ( 23 March 1921 – 4 January 1967 ) was a British speed record breaker who broke eight world speed records in the 1950s and 1960s.

* 1921 – David Greene, British director ( d. 2003 )

* 1921 – John Pritchard, British conductor ( d. 1989 )

* 1921 – Araucaria, British crossword compiler

Thus, the third phase of the war ( roughly August 1920 – July 1921 ) involved the IRA taking on a greatly expanded British force, moving away from attacking well defended barracks and instead using ambush tactics.

At the Crossbarry Ambush in March 1921, 100 or so of Barry's men fought a sizeable engagement with a British column of 1, 200, escaping from the British encircling manoeuvre.

In County Mayo, large scale guerrilla action did not break out until spring 1921, when two British forces were ambushed at Carrowkennedy and Tourmakeady.

By the end of the war, in July 1921, the IRA was very hard pressed by the deployment of more British troops into the most active areas and a chronic shortage of arms and ammunition.

During the 1920 Jerusalem riots, the 1921 Palestine riots and the 1929 Palestine riots, Palestinian Arabs manifested hostility against Zionist immigration and Jewish communities, which provoked the reaction of Jewish militias, sometimes supported by British troops.

* 1921 – Dachine Rainer, British writer ( d. 2000 )

* 1921 – Jack Clayton, British film director ( d. 1995 )

Assuming leadership of the Indian National Congress in 1921, Gandhi led nationwide campaigns for easing poverty, expanding women's rights, building religious and ethnic amity, ending untouchability, increasing economic self-reliance, and above all for achieving Swaraj — the independence of India from British domination.

* 1921 – Frank Searle, British Loch Ness Monster hoaxer ( d. 2005 )