R, r

[ahr]
|

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.

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

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

R

[ahr]

verb

Informal. are: Oysters R in season.

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.
registered trademark: written as superscript ® following a name registered with the U.S. Patent and Trademark Office.

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

R

2

Chemistry. radical.
Mathematics. ratio.
regular: a man's suit or coat size.
Electricity. resistance.
Theater. stage right.
Physics. roentgen.
Chess. rook.

r.

R.

1

or R.

(in prescriptions) take.

Origin of R.

1
From the Latin word recipe

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

r

R

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

R

symbol for

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

r.

abbreviation for

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

R.

r.

abbreviation for

registered (trademark)
right
river
rouble

R.

abbreviation for

rabbi
rector
Regina
Republican
response (in Christian liturgy)
Rex
River
Royal

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

Word Origin and History for r

R

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for r

r

abbr.

racemic

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

r

Abbreviation of radius

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.