r

1 of 4

noun

plural r's or rs ˈärz How to pronounce r (audio)
often capitalized, often attributive
1
a
: the 18th letter of the English alphabet
b
: a graphic representation of this letter
c
: a speech counterpart of orthographic r
2
: a graphic device for reproducing the letter r
3
: one designated r especially as the 18th in order or class
4
: something shaped like the letter R

r

2 of 4

abbreviation (1)

1
radius
2
rain
3
range
4
rare
5
real
6
recto
7
red
8
repeat
9
rerun
10
resistance
11
right
12
roentgen
13
rook
14
rough
15
run

R

3 of 4

abbreviation (2)

1
rabbi
2
radial
3
radical
used especially of a monovalent hydrocarbon radical
4
Rankine
5
Reaumur
6
recipe
7
registered trademark
often enclosed in a circle
8
regular
9
Republican
10
river
11
R-value
used to certify that a motion picture is of such a nature that admission is restricted to persons over a specified age (such as 17) unless accompanied by a parent or guardian
compare g, nc-17, pg, pg-13

Example Sentences

Noun There are two r's in “tomorrow.” “River” begins and ends with r.

Word History

First Known Use

Noun

before the 12th century, in the meaning defined at sense 1a

Time Traveler
The first known use of r was before the 12th century

Dictionary Entries Near r

Cite this Entry

“R.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/r. Accessed 7 Dec. 2022.

Kids Definition

r

1 of 2 noun
ˈär
often capitalized
: the 18th letter of the English alphabet

R

2 of 2 certification mark
used to certify that a motion picture is of such a nature that admission is restricted to persons over a specified age (as 17) unless accompanied by a parent or guardian

Medical Definition

r

1 of 3 abbreviation
roentgen

R

2 of 3 abbreviation
1
Reaumur
2
rough
used in bacteriology

R

3 of 3 symbol
chemical group and especially an organic chemical group
thiols have the general formula RSH

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