Phi (letter)

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Look up Φ, φ in Wiktionary, the free dictionary.
Greek alphabet
Αα Alpha Νν Nu
Ββ Beta Ξξ Xi
Γγ Gamma Οο Omicron
Δδ Delta Ππ Pi
Εε Epsilon Ρρ Rho
Ζζ Zeta Σσς Sigma
Ηη Eta Ττ Tau
Θθ Theta Υυ Upsilon
Ιι Iota Φφ Phi
Κκ Kappa Χχ Chi
Λλ Lambda Ψψ Psi
Μμ Mu Ωω Omega
Obsolete letters
Digamma Qoppa
San Sampi
Other characters
Stigma Sho
Heta

Greek diacritics

Phi (uppercase Φ, lowercase φ or ϕ), pronounced [fi] in modern Greek and as [faɪ] in English, is the 21st letter of the Greek alphabet. In modern Greek, it represents [f], a voiceless labiodental fricative. In Ancient Greek it represented [], an aspirated voiceless bilabial plosive (from which English ultimately inherits the spelling "ph" in words derived from Greek). In the system of Greek numerals it has a value of 500 (φʹ) or 500,000 (͵φ). The Cyrillic letter Ef (Ф, ф) arose from phi.

The lower-case letter \varphi \, (or often its variant, \phi \,) is used as a symbol for:

The upper-case letter Φ is used as a symbol for:

The diameter symbol in engineering, , is often incorrectly referred to as "phi". This symbol is used to indicate the diameter of a circular section, for example "⌀14", means the diameter of the circle is 14 units.

[edit] Computing

In Unicode, there are multiple forms of the phi letter:

  • Uppercase:
    • U+03A6 GREEK CAPITAL LETTER PHI (Φ): used in Greek texts
  • Lowercase:

In HTML/XHTML, the upper and lower case phi character entity references are Φ (Φ) and φ (φ) respectively.

In LaTeX, the math symbols are \Phi (\Phi\,\!), \phi (\phi\,\!), and \varphi (\varphi\,\!).

In some browsers (e.g. Internet Explorer 6), the shapes of the U+03C6 GREEK SMALL LETTER PHI (which should be viewed as a curl) and U+03D5 GREEK PHI SYMBOL (which should be viewed as a circle crossed by a slash) are exchanged. Compare these samples to check your browser:

Character Name Correct appearance Your browser
U+03C6 GREEK SMALL LETTER PHI \varphi\,\! φ
U+03D5 GREEK PHI SYMBOL \phi\,\! ϕ

[edit] See also

[edit] References

Look up Phi in Wiktionary, the free dictionary.
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