# φ

See also: Φ [U+03A6 GREEK CAPITAL LETTER PHI], ф [U+0444 CYRILLIC SMALL LETTER EF], Ф [U+0424 CYRILLIC CAPITAL LETTER EF], Փ [U+0553 ARMENIAN CAPITAL LETTER PIWR], and φ.

 φ U+03C6, φ GREEK SMALL LETTER PHI
 ← υ[U+03C5] Greek and Coptic χ →[U+03C7]
 𝜑 U+1D711, 𝜑 MATHEMATICAL ITALIC SMALL PHI
 ← 𝜐[U+1D710] Mathematical Alphanumeric Symbols 𝜒 →[U+1D712]

## Translingual

### Etymology 1

Named after Ancient Greek Φειδίας (Pheidías) ("Phidias"), who supposedly used the golden ratio in his work, by mathematician Mark Barr.

#### Symbol

φ

English Wikipedia has an article on:
Wikipedia
1. The golden ratio, an irrational number with a value of approximately 1.618033988 which expresses the relationship that the sum of two quantities is to the larger quantity as the larger is to the smaller.

### Etymology 2

#### Symbol

φ

1. Euler's totient function, an arithmetic function that counts totatives

## Ancient Greek

### Etymology

Derived from its majuscule counterpart Φ.

### Letter

φ (ph) (lowercase, uppercase Φ)

1. Lower-case phi (φεῖ), the 21st letter of the ancient Greek alphabet. It represented the voiceless aspirated bilabial plosive /pʰ/ and later the voiceless labiodental fricative /f/. It is preceded by υ and followed by χ.