Ef (Ф, ф) is the twenty-first letter of the Cyrillic alphabet.
It was directly derived from the Greek letter phi (Φ). Additionally, it has replaced Fita (Ѳ) in the Russian language version of the alphabet since 1918. Unlike phi, however, it is transliteration as "f", not "ph".
== See also ==
''For the latin alphabet letter, see F.''