definitions

R, r

[ ahr ]
/ ɑr /

noun, plural R's or Rs, r's or rs.

the 18th letter of the English alphabet, a consonant.
any spoken sound represented by the letter R or r, as in ran, carrot, or rhyme.
something having the shape of R.
a written or printed representation of the letter R or r.
a device, as a printer's type, for reproducing the letter R or r.
three R's.

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Definition for r (2 of 10)

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.

Definition for r (3 of 10)

r

Definition for r (4 of 10)

R

[ ahr ]
/ ɑr /

verb

Informal. are: Oysters R in season.

Definition for r (5 of 10)

R

Symbol.

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

Definition for r (6 of 10)

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 of R

1
abbreviation for restricted

Definition for r (7 of 10)

R

2

Definition for r (8 of 10)

r.

Definition for r (9 of 10)

R.

1

or R.

(in prescriptions) take.

Origin of R.

1
From the Latin word recipe

Definition for r (10 of 10)

R.

2

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for r

British Dictionary definitions for r (1 of 5)

r

R

/ (ɑː) /

noun plural r's, R's or Rs

the 18th letter and 14th consonant of the modern English alphabet
a speech sound represented by this letter, in English usually an alveolar semivowel, as in red
See three Rs

British Dictionary definitions for r (2 of 5)

R

symbol for

British Dictionary definitions for r (3 of 5)

r.

abbreviation for

rare
recto
Also: r rod (unit of length)
ruled
cricket baseball run(s)

British Dictionary definitions for r (4 of 5)

R.

r.

abbreviation for

registered (trademark)
right
river
rouble

British Dictionary definitions for r (5 of 5)

R.

abbreviation for

Word Origin for R.

(sense 3) Latin: Queen (sense 6) Latin: King
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for r (1 of 2)

r

abbr.

racemic

Medicine definitions for r (2 of 2)

R

abbr.

right
radical (usually an alkyl or aryl group)
respiration
respiratory exchange ratio
or r roentgen
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for r (1 of 2)

r

Abbreviation of radius

Science definitions for r (2 of 2)

R

The symbol for resistance.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with r

R

see three R's.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.