## What is the rho symbol?

Generally speaking, the sign “rho” is the 17th letter derived from the Greek alphabet. In the system of Greek numerals, the rho symbol has a value of 100. The rho symbol is originated right from the Phoenician letter “res” Phoenician “res.svg.” The uppercase form of the rho sign uses the same glyph, “Ρ,” as the distinct Latin letter “P,” but these two letters use different Unicode character encodings. The rho symbol is widely approved and designated as an uppercase Latin “Ρ” letter, as lowercase “ρ” or often written like this: “ϱ.” As of Greek alphabet rho letter, it must be said that the rho symbol is written like this: ῥῶ.

## Usage of the rho symbol

The rho symbol is classed as a liquid consonant and lambda, and often, the nasals nu and mu have main implications for morphology. In Ancient and Modern Greek, the rho symbol resembles a trapped or trilled r. While in polytonic orthography, the rho symbol at the beginning of a word is written with rough breathing, similar to h (ῥ RH). A double rho in a name registered with smooth breathing over the 1st rho and raspy breathing over the 2nd (ῤῥ RRH).

That mainly reflected a voiceless or an aspirated pronunciation in Ancient Greek, which led to multiple Greek-origin English words contain “rrh” in a word or start a word with “rh.”

## Rho symbol in alphabets

- Chi Rho - The symbol rho is overlaid with chi forms in the Chi-Rho symbol, signifying Jesus Christ.
- The rho symbol with stroke (ϼ) - The rho symbol with a stroke via its tail is commonly used for abbreviations including rho, most notably in γϼ for γράμμα as a unit of measurement.
- The name of the symbol rho is written in the Greek alphabet as ρω/ρο (monotonic) or ῥῶ (polytonic). Greek letters that arose from the symbol "rho" have Cyrillic Er (Р) and Roman R letters.

## Rho symbol used in math and physical sciences

The rho symbols ρ and ϱ are used outside the Greek alphabet in math and physical sciences. In physical science, it represents:

- mass density, air density, or charge density (ρ)
- Resistivity (ρ)
- Rho meson (ρ+, ρ−, ρ0)
- Reaction constant, independent of the nature and position of the substituents of the benzene ring.

In mathematics rho symbol represents:

- A length coordinate in spherical, polar, cylindrical, and toroidal coordinate systems.
- It signifies the correlation coefficient of a population parameter.
- The plastic number
- The prime constant

In computer programming, the rho symbol stands for:

- LaTeX: \rho ({\displaystyle \rho }\rho ), and \varrho ({\displaystyle \varrho }\varrho).
- The lowercase rho "⍴" signifies reshape in the APL programming language. Also, by extension, it queries shape.
- The lowercase rho "ρ" is used for the unary rename in relational algebra.
- In statistics, the rho symbol represents the rank correlation of Spearman's coefficient, widely known as “Spearman's rho.”

## Rho symbol encodings

- To insert ϱ use Unicode in decimal 1009, or hex code U+03F1; UTF-8 code in decimal 207 177, or hex code CF B1.
- To insert ϼ use Unicode in decimal 1020, or hex code U+03FC; UTF-8 code in decimal 207 188, or hex code CF BC.
- To insert ᴩ use Unicode in decimal 7465, or hex code U+1D29; UTF-8 code in decimal 225 180 169, or hex code E1 B4 A9.
- To insert ᵨ use Unicode in decimal 7528, in hex code U+1D68; UTF-8 code in decimal 225 181 168, or hex code E1 B5 A8.
- To insert ☧ sign, use Unicode in decimal 9767, or hex code U+2627; UTF-8 code in decimal 226 152 167, or hex code E2 98 A7.

Below you will find Greek rho symbol character encodings:

- To insert Ρ, use Unicode in decimal 929, or hex code U+03A1.
- To insert ρ, use Unicode in decimal 961, or hex code U+03C1.
- To insert Ῥ use Unicode in decimal 8172, or hex code U+1FEC.
- To insert ῥ use Unicode in decimal 8165, or hex code U+1FE5.
- To insert ῤ use Unicode in decimal 8164, or hex code U+1FE4.