R

R, r

[ahr]
noun, plural R's or Rs, r's or rs.
1.
the 18th letter of the English alphabet, a consonant.
2.
any spoken sound represented by the letter R or r, as in ran, carrot, or rhyme.
3.
something having the shape of R .
4.
a written or printed representation of the letter R or r.
5.
a device, as a printer's type, for reproducing the letter R or r.
Dictionary.com Unabridged

R

[ahr]
verb
Informal. are : Oysters R in season.

R

1
restricted: a rating assigned to a motion picture by the Motion Picture Association of America indicating that children under the age of 17 will not be admitted unless accompanied by an adult. Compare G ( def 7 ), PG, PG-13, X ( def 8 ).

Origin:
abbreviation for restricted

R

2
1.
Chemistry, radical.
2.
Mathematics, ratio.
3.
regular: a man's suit or coat size.
4.
Electricity, resistance.
5.
Theater. stage right.
6.
Physics. roentgen.
7.
Chess. rook.

R

Symbol.
1.
the 18th in order or in a series, or, when I is omitted, the 17th.
2.
(sometimes lowercase) the medieval Roman numeral for 80. Compare Roman numerals.
3.
Biochemistry, arginine.
5.
registered trademark: written as superscript ® following a name registered with the U.S. Patent and Trademark Office.

r

2.
Commerce, registered ( def 2 ).
3.
Electricity, resistance.
4.
Physics. roentgen ( def 2 ).
7.
plural rs, rupee.

r

Ecology.
the theoretical intrinsic rate of increase of a population, equivalent to the difference between the birth and death rates divided by the number of individuals in the population.
Also called Malthusian parameter.

R.

1
(in prescriptions) take.
Also, R.


Origin:
< Latin recipe

R.

2
6.
(in South Africa) rand; rands.
10.
13.
14.
15.
16.
17.
18.
19.
Theater. stage right.

r.

5.
6.
Commerce, received.
8.
replacing.
10.
11.
rises.
12.
13.
14.
15.
16.
17.
18.
Baseball. run; runs.
19.
plural rs. rupee.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Collins
World English Dictionary
r or R (ɑː)
 
n , pl r's, R's, Rs
1.  the 18th letter and 14th consonant of the modern English alphabet
2.  a speech sound represented by this letter, in English usually an alveolar semivowel, as in red
3.  See three Rs
 
R or R
 
n

R
 
symbol for
1.  chem radical
2.  currency
 a.  rand
 b.  rupee
3.  Réaumur temperature (scale)
4.  physics, electronics resistance
5.  roentgen or röntgen
6.  chess rook
7.  Royal
8.  chem gas constant
9.  in the US and Australia
 a.  restricted exhibition (used to describe a category of film certified as unsuitable for viewing by anyone under the age of 18)
 b.  (as modifier): an R film

r.
 
abbreviation for
1.  rare
2.  recto
3.  Also: r rod (unit of length)
4.  ruled
5.  cricket, baseball run(s)

R.
 
abbreviation for
1.  rabbi
2.  rector
3.  Regina
4.  Republican
5.  response (in Christian liturgy)
6.  Rex
7.  River
8.  Royal
 
[(sense 6) Latin: King]

R. or r.
 
abbreviation for
1.  registered (trademark)
2.  right
3.  river
4.  rouble
 
r. or r.
 
abbreviation for

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Etymonline
Word Origin & History

R
In a circle, meaning "registered (trademark)," first incorporated in U.S. statues 1946. Three Rs (1825) said to have been given as a toast by Sir W. Curtis (1752-1829). R&R "rest and relaxation," first recorded 1953, Amer.Eng.; R&B "rhythm and blues" (type of popular music) first attested 1949, Amer.Eng.
Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
American Heritage
Medical Dictionary

r abbr.
racemic

R abbr.

  1. radical (usually an alkyl or aryl group)

  2. respiration

  3. respiratory exchange ratio

  4. or r roentgen

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
r  
Abbreviation of radius
R  
The symbol for resistance.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
American Heritage
Abbreviations & Acronyms
r
  1. correlation coefficient

  2. radius

  3. resistance

R
  1. gas constant

  2. radical

  3. rain

  4. range

  5. Réaumur

  6. receiver

  7. registered trademark

  8. Republican

  9. response

  10. restricted (children under 17 must be accompanied by a parent or guardian)

  11. right

  12. roentgen

  13. rook

  14. run

r.
  1. rare

  2. recto

  3. reigned

  4. retired

  5. rod

  6. rubber

  7. ruble

  8. rupee

R.
  1. patented

  2. rabbi

  3. received as transmitted (shortwave transmission)

  4. rector

  5. registered

  6. Latin rex (king)

  7. Latin regina (queen)

  8. river

The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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American Heritage
Idioms & Phrases

R

see three R's.

The American Heritage® Dictionary of Idioms by Christine Ammer.
Copyright © 1997. Published by Houghton Mifflin.
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Encyclopedia Britannica
Encyclopedia

r

unit of X-radiation or gamma radiation, the amount that will produce, under normal conditions of pressure, temperature, and humidity, in 1 kg (2.2 lbs) of air, an amount of positive or negative ionization equal to 2.58104 coulomb. It is named for the German physicist Wilhelm Conrad Rontgen. See also rem.

Learn more about R with a free trial on Britannica.com.

Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Idioms & Phrases
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