Cyrillic letter Ef
Phonetic usage:	[f], [ɸ]
Name (Early Cyrillic alphabet):	фрьтъ
Numeric value:	500
Derived from:	Greek letter Phi (Φ φ)
The Cyrillic script
Slavic letters
А А́ А̀ А̂ А̄ Ӑ Ӓ Б В Г Ґ Д Ђ Ѓ Е Е́ Ѐ Е̂ Е̄ Ё Є Є́ Ж З З́ Ѕ И І І́ Ї Ꙇ И́ Ѝ И̂ Ӣ Й Ӥ Ј К Л Љ М Н Њ О О́ О̀ О̂ О̄ Ӧ П Р С С́ Т Ћ Ќ У У́ У̀ У̂ Ӯ Ў Ӱ Ф Х Ц Ч Џ Ш Щ Ꙏ Ъ Ъ̀ Ы Ы́ Ь Ѣ Э Э́ Ю Ю́ Ю̀ Я Я́ Я̀ ʼ ˮ
Non-Slavic letters
А̊ А̃ Ӓ̄ Ӕ Ә Ә́ Ә̃ Ӛ В̌ Ԝ Г̑ Г̇ Г̣ Г̌ Г̂ Г̆ Г̈ г̊ Ҕ Ғ Ӻ Ғ̌ ғ̊ Ӷ Г̡ Д́ Д̌ Д̈ Д̣ Д̆ Ӗ Е̃ Ё̄ Є̈ Ԑ Ԑ̈ Җ Ӝ Ӂ Ж̣ Ҙ Ӟ З̌ З̣ З̆ Ӡ И̃ Ҋ Қ Ӄ Ҡ Ҟ Ҝ К̣ к̊ қ̊ Ԛ ᴫ Л́ Ӆ Ԯ Ԓ Л̈ Ӎ ᵸ Н́ Ӊ Ң Ԩ Ӈ Ҥ О̆ О̃ Ӧ̄ Ө Ө̄ Ө́ Ө̆ Ӫ Ԥ П̈ Р̌ Ҏ С̌ Ҫ С̣ С̱ Т́ Т̈ Т̌ Т̇ Т̣ Ҭ Ᲊ У̃ Ӳ У̊ Ӱ̄ Ұ Ү Ү́ Х̣ Х̱ Х̮ Х̑ Х̌ Ҳ Ӽ х̊ Ӿ ӿ̊ Һ Һ̈ Ԧ Ц̌ Ц̈ Ҵ Ҷ Ҷ̣ Ӵ Ӌ Ҹ Ч̇ Ч̣ Ҽ Ҿ Ш̣ ꚜ Ы̆ Ы̄ Ӹ ꚝ Ҍ Ҩ Э̆ Э̄ Э̇ Ӭ Ӭ́ Ӭ̄ Ю̆ Ю̈ Ю̄ Я̆ Я̄ Я̈ Ӏ
Archaic or unused letters
А̨ Б̀ Б̣ Б̱ В̀ Г̀ Г̧ Г̄ Г̓ Г̆ Ҕ̀ Ҕ̆ Ԁ Д̓ Д̀ Д̨ Ԃ Ꚁ Ꙣ Е̇ Е̨ Ж̀ Ж̑ Ꙃ Ꙅ Џ̆ Ꚅ Ꚅ̆ Ꙁ З̀ З̑ Ԅ Ԇ Ꚉ Ԫ Ꚃ Ꚕ І̂ І̣ І̨ Ј̵ Ј̃ Ꙉ К̓ К̀ К̆ Ӄ̆ К̑ К̇ К̈ К̄ Ԟ К̂ Л̀ Ԡ Ꙥ Ԉ Л̑ Л̇ Ԕ М̀ М̃ Ꙧ Н̀ Н̄ Н̧ Н̃ Ԋ Ԣ Н̡ Ѻ Ꙩ Ꙫ Ꙭ ꙮ Ꚙ Ꚛ П̓ П̀ П́ Ҧ П̧ П̑ Ҁ Ԛ̆ Р́ Р̀ Р̃ Ԗ С̀ С̈ Ԍ Ҫ̓ Т̓ Т̀ Ԏ Т̑ Ꚋ Т̧ Ꚍ Ꚍ̆ Ѹ Ꙋ У̇ У̨ ꙋ́ Ф̑ Ф̓ Х́ Х̀ Х̆ Х̇ Х̧ Х̾ Х̓ һ̱ Ѡ Ꙍ Ѽ Ѿ Ꙡ Ц̀ Ц́ Ц̓ Ꚏ Ꚏ̆ Ꚑ Ч́ Ч̀ Ч̆ Ч̑ Ч̓ Ԭ Ꚓ Ꚇ Ꚇ̆ Ҽ̆ Ш̀ Ш̆ Ш̑ Щ̆ Ꚗ Ꚗ̆ Ъ̄ Ъ̈ Ъ̈̄ Ꙑ Ы̂ Ы̃ Ѣ́ Ѣ̈ Ѣ̆ Ꙓ Э̨ Э̂ Ꙕ Ю̂ Ꙗ Я̂ Я̨ Ԙ Ѥ Ѧ Ꙙ Ѫ Ꙛ Ѩ Ꙝ Ѭ Ѯ Ѱ Ѳ Ѵ Ѷ Ꙟ
List of Cyrillic letters List of Cyrillic multigraphs

Ef or Fe (Ф ф; italics: Ф ф) is a Cyrillic letter, commonly representing the voiceless labiodental fricative /f/, like the pronunciation of ⟨f⟩ in "fill, flee, or fall". The Cyrillic letter Ef is romanized as ⟨f⟩.

The Cyrillic letter Ef was derived from the Greek letter Phi (Φ φ). It merged with and eliminated the letter Fita (Ѳ) in the Russian alphabet in 1918.

The name of Ef in the Early Cyrillic alphabet is фрьтъ (fr̥tŭ or frĭtŭ), in later Church Slavonic and Russian form it became фертъ (fert).^[1]

In the Cyrillic numeral system, Ef has a value of 500.

The Slavic languages have almost no native words containing /f/. This sound did not exist in Proto-Indo-European (PIE). It arose in Greek and Latin from PIE *bʰ (which yielded Slavic /b/). In some instances in Latin, it represented historical th-fronting and derived from Proto-Indo-European *dʰ. In the Germanic languages, the f sound arose from PIE *p via Grimm's law, which remained unchanged in Slavic. The letter ф is thus almost exclusively found in words of foreign origin, especially Greek (from φ and sometimes from θ), Latin, French, German, Dutch, English, and Turkic languages

Example borrowings in Russian:

• from Greek: катастрофа, "catastrophe" (from φ); Фёдор, "Theodore" (from θ)
• from Latin: федерация, "federation"; эффект, "effect"
• from German: картофель, "potato" (from Kartoffel); фунт, "pound" (from Pfund)
• from Dutch: флаг, "flag"

The few native Slavic words with this letter (in different languages) are examples of onomatopoeia (like Russian verbs фукать, фыркать etc.) or reflect sporadic pronunciation shifts:

• from пв /pv/: Serbian уфати 'to hope' (cf. Church Slavonic уповати 'to hope')
• from хв /xv/: Macedonian сфати '(he) understands' (cf. Church Slavonic схватити 'to take, to catch'), Russian дрофа 'bustard' (cf. Ukrainian дрохва 'bustard')
• from кв /kv/: Russian филин 'eagle-owl' (cf. Ukrainian квилити 'to cry')
• from х /x/: Russian toponym Фили 'Fili' (from хилый 'sickly')

Ef is the 21st letter of the Bulgarian alphabet; the 22nd letter of the Russian alphabet; the 23rd letter of the Belarusian alphabet; the 25th letter of the Serbian and Ukrainian alphabet; and the 26th letter of the Macedonian alphabet. It represents the consonant /f/ unless it is before a palatalizing vowel, when it represents /fʲ/.

• Φ φ/ϕ : Greek letter Phi
• Ѳ ѳ : Cyrillic letter Fita
• F f : Latin letter F
• Փ փ : Armenian letter Piwr
• Q q Latin letter Q
• Ჶ ჶ Fi (letter)

The phraseologism "стоять фертом", "to stand as fert" means "to stand with arms akimbo".

• The dictionary definition of Ф at Wiktionary
• The dictionary definition of ф at Wiktionary