Rho (Ρ or ρ) is a letter of the Greek alphabet. Rho or RHO also may refer to:

Science and medicine

• Rho family of GTPases

• RHOA
• RHOB
• RhoC

• RHO (gene), or Rhodopsin

ρ as a conventional symbol

in mathematics

• A length coordinate in coordinate systems with both length and angle coordinates:
  • Polar coordinate system
  • Spherical coordinate system
  • Cylindrical coordinate system
  • Toroidal coordinate system
  • Toroidal and poloidal coordinates of the Earth's magnetic field
• Spectral radius of a square matrix
• Pollard's rho algorithm
• Pollard's rho algorithm for logarithms
• Prime constant
• Plastic ratio

in physics

• Density of a material
• Volume charge density
• Resistivity of a material
• Rho meson

in biology

• Rho factor protein in RNA transcription termination
• Ecology, population damping ratio where ρ = λ1 / |λ2|.

in statistics

• Spearman's rank correlation coefficient
• Pearson product-moment correlation coefficient

in other fields

• The reaction constant in the Hammett equation in chemistry
• Rho (finance)

Toponyms

• Rho, Lombardy, a town in Italy
• Rho Island, a.k.a. Ro, Greece
• Rho River, tributary of the Dora di Bardonecchia, Italy

Acronyms and abbreviations RHO

• Right-Hand Opponent, in contract bridge
• Red Hot Organization, HIV/AIDS-related charity
• Rhodes International Airport, in Greeter using

People

• Giacomo Rho (1593-1638), Italian Jesuit missionary in China

See also

• Ro (disambiguation)