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This article is about the letter of the alphabet. For other uses, see R (disambiguation).
Circle sheer blue 29.gif
Circle sheer blue 29.gif
Cursive script 'r' and capital 'R'
R cursiva.gif

R (named ar /ˈɑː/[1]) is the 18th letter of the ISO basic Latin alphabet.


Egyptian hieroglyph
Later Etruscan R
PhoenicianR-01.pngEtruscanR-01.svgRho uc lc.svgEtruscanR-02.svg

The original Semitic letter may have been inspired by an Egyptian hieroglyph for tp, "head". It was used for /r/ by Semites because in their language, the word for "head" was rêš (also the name of the letter). It developed into Greek 'Ρ' ῥῶ (rhô) and Latin R. It is likely that some Etruscan and Western Greek forms of the letter added the extra stroke to distinguish it from a later form of the letter P.[citation needed]

The name of the letter in Latin was er (/ɛr/), following the pattern of other letters representing continuants, such as F, L, M, N, and S. This name is preserved in French and many other languages. In Middle English, the name of the letter changed from /ɛr/ to /ar/, following a pattern exhibited in many other words such as farm (compare French ferme), and star (compare German Stern).

The minuscule (lowercase) form as 'r' developed through several variations on the capital form. In handwriting it was common not to close the bottom of the loop but continue into the leg, saving an extra pen stroke. The loop-leg stroke shortened into the simple arc used today. Another minuscule, r rotunda (ꝛ), kept the loop-leg stroke but dropped the vertical stroke, although it fell out of use around the 18th century.


The letter R is the eighth most common letter in English and the fourth-most common consonant (after 't', 'n', and 's').[2] R represents a rhotic consonant in many languages, as shown in the table below. The International Phonetic Alphabet uses several variations of the letter to represent the different rhotic consonants; [r] represents the alveolar trill.

Alveolar trill [r]Listensome dialects of British English or in emphatic speech, standard Dutch, Finnish, Galician, German in some dialects, Hungarian, Icelandic, Italian, Czech, Lithuanian, Latvian, Latin, Norwegian mostly in the northwest, Polish, Catalan, Portuguese (traditional form), Romanian, Scots, Spanish and Albanian 'rr', Swedish, Welsh
Alveolar approximant [ɹ]ListenEnglish (most varieties), Dutch in some Dutch dialects (in specific positions of words), Faroese, Sicilian
Alveolar flap / Alveolar tap [ɾ]ListenPortuguese, Catalan, Spanish and Albanian 'r', Turkish, Dutch, Italian, Venetian, Galician, Leonese, Norwegian, Irish
Voiced retroflex fricative [ʐ]ListenNorwegian around Tromsø, Spanish used as an allophone of /r/ in some South American accents; Standard Chinese (in pinyin); Vietnamese (southern dialects)
Retroflex approximant [ɻ]Listensome English dialects (in America, South West England, and Dublin), Standard Chinese (in pinyin), Gutnish
Retroflex flap [ɽ]ListenNorwegian when followed by <d>, sometimes in Scottish English
Uvular trill [ʀ]ListenGerman stage standard; some Dutch dialects (in Brabant and Limburg, and some city dialects in The Netherlands), Swedish in Southern Sweden, Norwegian in western and southern parts
Voiced uvular fricative [ʁ]ListenGerman, Danish, French, standard European Portuguese 'rr', standard Brazilian Portuguese 'rr', Puerto Rican Spanish 'rr' and 'r-', Norwegian in western and southern parts.

Other languages may use the letter 'r' in their alphabets (or Latin transliterations schemes) to represent rhotic consonants different from the alveolar trill. In Haitian Creole, it represents a sound so weak that it is often written interchangeably with 'w', e.g. 'Kweyol' for 'Kreyol'.

Brazilian Portuguese has a great number of allophones of /ʁ/ such as [χ], [h], [ɦ], [x], [ɣ], [ɹ] and [r], the latter three ones can be used only in certain contexts ([ɣ] and [r] as 'rr'; [ɹ] in the syllable coda, as an allophone of /ɾ/ according to the European Portuguese norm and /ʁ/ according to the Brazilian Portuguese norm). Usually at least two of them are present in a single dialect, such as Rio de Janeiro's [ʁ], [χ], [ɦ] and, for a few speakers, [ɣ].

In science, the letter R is a symbol for the gas constant. Mathematicians use 'R' or \mathbb{R} (an R in blackboard bold, displayed as in Unicode) for the set of all real numbers.


The letter R is the only letter in the basic modern Latin alphabet in which the uppercase has a closed section and the lowercase does not.

Dog's letter[edit]

The letter R is sometimes referred to as the littera canina (canine letter). This phrase has Latin origins: the Latin R was trilled to sound like a growling dog. A good example of a trilling R is the Spanish word for dog, perro.[3]

In William Shakespeare's Romeo and Juliet, such a reference is made by Juliet's nurse in Act 2, scene 4, when she calls the letter R "the dog's name." The reference is also found in Ben Jonson's English Grammar.[4]

Related letters and other similar characters[edit]

Computing codes[edit]

Numeric character reference&#82;&#x52;&#114;&#x72;
EBCDIC family217D915399
ASCII 1825211472
1 Also for encodings based on ASCII, including the DOS, Windows, ISO-8859 and Macintosh families of encodings.

Other representations[edit]

NATO phoneticMorse code
ICS Romeo.svgSemaphore Romeo.svg⠗
Signal flagFlag semaphoreBraille

See also[edit]


  1. ^ "R", Oxford English Dictionary, 2nd edition (1989); "ar", op. cit.
  2. ^ English Letter Frequency
  3. ^ "A Word A Day: Dog's letter". Wordsmith.org. Retrieved 2012-01-17. 
  4. ^ Shakespeare, William; Horace Howard Furness; Frederick Williams (1913). Romeo and Juliet. Lippincott. p. 189. 

External links[edit]