Rho

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For other uses, see Rho (disambiguation).

Rho (/ˈr/; uppercase Ρ, lowercase ρ or ϱ) is the 17th letter of the Greek alphabet. In the system of Greek numerals, it has a value of 100. It is derived from Phoenician letter res Phoenician res.svg. Its uppercase form is not to be confused with the Latin letter P, although both are typeset using the same glyph.

Uses[edit]

The Greek alphabet on a black figure vessel, with an R-shaped rho.

Greek[edit]

Rho is classed as a liquid consonant (together with lambda and sometimes the nasals mu and nu), which has important implications for morphology. In both Ancient and Modern Greek, it represents a trilled or tapped r.

In polytonic orthography a rho at the beginning of a word is written with a rough breathing (equivalent to h) — rh — and a double rho within a word is written with a smooth breathing over the first rho and a rough breathing over the second — ῤῥ rrh — apparently reflecting an aspirated or voiceless pronunciation in Ancient Greek, hence the various Greek-derived English words that start with rh or contain rrh.

The name of the letter is written in Greek as ῥῶ (polytonic) or ρω/ρο (monotonic).

Other alphabets[edit]

Letters that arose from rho include Roman R and Cyrillic Er (Р).

Mathematics and science[edit]

The characters Ρ, ρ and ϱ are also used outside its Greek alphabetical context in science and mathematics.

Chi Rho[edit]

The letter rho overlaid with chi forms the Chi Rho symbol, used to represent Jesus Christ.

Rhodes Scholars[edit]

Former Rhodes Scholars are entitled to use the Greek letter rho as a designation of their status. When used, the symbol should precede the name.[1]

Character encodings[edit]

Greek Rho[2][edit]

CharacterΡρ
Unicode nameGREEK CAPITAL LETTER RHOGREEK SMALL LETTER RHOGREEK CAPITAL LETTER RHO WITH DASIAGREEK SMALL LETTER RHO WITH DASIAGREEK SMALL LETTER RHO WITH PSILI
Encodingsdecimalhexdecimalhexdecimalhexdecimalhexdecimalhex
Unicode929U+03A1961U+03C18172U+1FEC8165U+1FE58164U+1FE4
UTF-8206 161CE A1207 129CF 81225 191 172E1 BF AC225 191 165E1 BF A5225 191 164E1 BF A4
Numeric character referenceΡΡρρῬῬῥῥῤῤ
Named character referenceΡρ
DOS Greek14490168A8
DOS Greek-2199C7235EB
Windows 1253209D1241F1
TeX\rho

Greek Rho symbols[edit]

Characterϱϼ
Unicode nameGREEK RHO SYMBOLGREEK RHO WITH STROKE SYMBOLGREEK LETTER SMALL CAPITAL RHOGREEK SUBSCRIPT SMALL LETTER RHOCHI RHO
Encodingsdecimalhexdecimalhexdecimalhexdecimalhexdecimalhex
Unicode1009U+03F11020U+03FC7465U+1D297528U+1D689767U+2627
UTF-8207 177CF B1207 188CF BC225 180 169E1 B4 A9225 181 168E1 B5 A8226 152 167E2 98 A7
Numeric character referenceϱϱϼϼᴩᴩᵨᵨ☧☧
TeX\varrho

Coptic Ro[edit]

Character
Unicode nameCOPTIC CAPITAL LETTER ROCOPTIC SMALL LETTER ROCOPTIC SYMBOL CHI RHO
Encodingsdecimalhexdecimalhexdecimalhex
Unicode11426U+2CA211427U+2CA311497U+2CE9
UTF-8226 178 162E2 B2 A2226 178 163E2 B2 A3226 179 169E2 B3 A9
Numeric character referenceⲢⲢⲣⲣ⳩⳩

Technical Symbol[edit]

Character
Unicode nameAPL FUNCTIONAL SYMBOL RHO
Encodingsdecimalhex
Unicode9076U+2374
UTF-8226 141 180E2 8D B4
Numeric character reference⍴⍴

Mathematical Rho[edit]

Character𝚸𝛒𝛠𝛲𝜌
Unicode nameMATHEMATICAL BOLD
CAPITAL RHO
MATHEMATICAL BOLD
SMALL RHO
MATHEMATICAL BOLD
RHO SYMBOL
MATHEMATICAL ITALIC
CAPITAL RHO
MATHEMATICAL ITALIC
SMALL RHO
Encodingsdecimalhexdecimalhexdecimalhexdecimalhexdecimalhex
Unicode120504U+1D6B8120530U+1D6D2120544U+1D6E0120562U+1D6F2120588U+1D70C
UTF-8240 157 154 184F0 9D 9A B8240 157 155 146F0 9D 9B 92240 157 155 160F0 9D 9B A0240 157 155 178F0 9D 9B B2240 157 156 140F0 9D 9C 8C
UTF-1655349 57016D835 DEB855349 57042D835 DED255349 57056D835 DEE055349 57074D835 DEF255349 57100D835 DF0C
Numeric character reference𝚸𝚸𝛒𝛒𝛠𝛠𝛲𝛲𝜌𝜌
Character𝜚𝜬𝝆𝝔𝝧
Unicode nameMATHEMATICAL ITALIC
RHO SYMBOL
MATHEMATICAL BOLD ITALIC
CAPITAL RHO
MATHEMATICAL BOLD ITALIC
SMALL RHO
MATHEMATICAL BOLD ITALIC
RHO SYMBOL
MATHEMATICAL SANS-SERIF
BOLD CAPITAL RHO
Encodingsdecimalhexdecimalhexdecimalhexdecimalhexdecimalhex
Unicode120602U+1D71A120620U+1D72C120646U+1D746120660U+1D754120679U+1D767
UTF-8240 157 156 154F0 9D 9C 9A240 157 156 172F0 9D 9C AC240 157 157 134F0 9D 9D 86240 157 157 148F0 9D 9D 94240 157 157 167F0 9D 9D A7
UTF-1655349 57114D835 DF1A55349 57132D835 DF2C55349 57158D835 DF4655349 57172D835 DF5455349 57191D835 DF67
Numeric character reference𝜚𝜚𝜬𝜬𝝆𝝆𝝔𝝔𝝧𝝧
Character𝞀𝞎𝞠𝞺𝟈
Unicode nameMATHEMATICAL SANS-SERIF
BOLD SMALL RHO
MATHEMATICAL SANS-SERIF
BOLD RHO SYMBOL
MATHEMATICAL SANS-SERIF
BOLD ITALIC CAPITAL RHO
MATHEMATICAL SANS-SERIF
BOLD ITALIC SMALL RHO
MATHEMATICAL SANS-SERIF
BOLD ITALIC RHO SYMBOL
Encodingsdecimalhexdecimalhexdecimalhexdecimalhexdecimalhex
Unicode120704U+1D780120718U+1D78E120736U+1D7A0120762U+1D7BA120776U+1D7C8
UTF-8240 157 158 128F0 9D 9E 80240 157 158 142F0 9D 9E 8E240 157 158 160F0 9D 9E A0240 157 158 186F0 9D 9E BA240 157 159 136F0 9D 9F 88
UTF-1655349 57216D835 DF8055349 57230D835 DF8E55349 57248D835 DFA055349 57274D835 DFBA55349 57288D835 DFC8
Numeric character reference𝞀𝞀𝞎𝞎𝞠𝞠𝞺𝞺𝟈𝟈

These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.

See also[edit]

References[edit]

  1. ^ "Oxford University Calendar: Notes on Style". Oxford University Gazette. 2011-03-03. Retrieved 2011-09-08. 
  2. ^ Unicode Code Charts: Greek and Coptic (Range: 0370-03FF)