da:Rho (bogstav) de:Rho es:Rho

Greek alphabet
Α α Alpha	Β β Beta
Γ γ Gamma	Δ δ Delta
Ε ε Epsilon	Ϝ ϝ Digamma
Ζ ζ Zeta	Η η Eta
Θ θ Theta	Ι ι Iota
Κ κ Kappa	Λ λ Lambda
Μ μ Mu	Ν ν Nu
Ξ ξ Xi	Ο ο Omicron
Π π Pi	Ϻ ϻ San
Ϙ ϙ Qoppa	Ρ ρ Rho
Σ σ Sigma	Τ τ Tau
Υ υ Upsilon	Φ φ Phi
Χ χ Chi	Ψ ψ Psi
Ω ω Omega	Ϡ ϡ Sampi

Rho (upper case Ρ, lower case ρ) is the 17th letter of the Greek alphabet. In the system of Greek numerals it has a value of 100.

Rho is generally classed as a liquid (together with lambda and sometimes the nasals mu and nu), which has important implications for morphology. It is pronounced similarly to the letter r in languages with a Latin-derived alphabet. In polytonic orthography a rho at the beginning of a word is conventionally written with a rough breathing (equivalent to h) and a double rho within a word is written with a smooth breathing over the first rho and a rough breathing over the second, apparently reflecting an aspirated or voiceless pronunciation in Ancient Greek, hence the various Greek-derived English words which start with rh or contain rrh. The name of the letter is written in Greek as ῥῶ (polytonic) or ρώ (monotonic).

Rho is used to designate a list of items in the APL programming language.

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

Lower case ρ is used in physics to represent density and resistivity.

See also

• Rho - for other meanings.