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21

21

928 1.0
The number after twenty and before twenty-two
  • numeral
translation icon : veintiuno
  • Cardinal Adeyemi, 21 votes.
  • 21 years
  • April 21
  • July 21

Examples

  • The second phase took place 21 months after entry into the longitudinal study.

    Academic text (2011)
  • In the 2018 cycle, about $21 billion.

  • But, when I turned 21, the place became mine.

  • It's been 21 days since we found the house, nothing's happened.

  • The participants range in age from 21 to 60, with the median age of 28.

    Academic text (2011)
  • After three years in Scotland, Fanny, now 21, grew bored with classical studies and intellectual discussions.

    Fiction book (1993)
  • I'm 21.

  • You're under 21.

  • The participants' age ranged from 21 to 59 years of age (M = 29.67, SD = 9.57).

    Academic text (2011)
  • The participants range in age from 21 to 60, with the median age of 28.

Synonyms

twenty-one
vs21
9 1.0

A number that comes after twenty

is shown as digits rather than spelled-out words
XXI
vs21
1 4.7

A Roman numeral for twenty-one

is shown as digits rather than as Roman numerals

Compounds

1 1.0

The day when the sun is farthest north and daylight is longest north of the equator

atomic number 21
  • Specialized
7.8

A light white metal called scandium that people use in alloys to make things stronger

2.3

The day when people worldwide hold public yoga sessions for the International Day of Yoga

trisomy 21
  • Specialized
4.6

A condition present at birth caused by an extra 21st chromosome that affects learning and development

Surface Forms

21 cardinal digit
twenty-one cardinal word
twenty one cardinal word
21st ordinal digit
twenty-first ordinal word
twenty first ordinal word

Etymology

The number 21 is read as twenty-one, made from twenty and one. A helpful way to remember it is that twenty means 'two tens' and adding one means 'one more', so 21 is 'two tens and one', the number after twenty.