Kaph

Kaph is thought to be derived from a pictogram of the palm of a hand (in both modern Arabic and Hebrew, kaph כַּף means "palm" or "grip"), though in Arabic the a in the name of the letter (كاف) is pronounced longer than the a in the word meaning "palm" (كَف). The small ک above the kāf in its final and isolated forms ⟨ك  ـك⟩ was originally ‘alāmatu-l-ihmāl, but became a permanent part of the letter. Previously this sign could also appear above the medial form of kāf, instead of the stroke on its ascender.

The letter is named kāf, and it is written in several ways depending on its position in the word.

There are four variants of the letter:

• The basic form is used for the Arabic language and many other languages and is the Naskh glyph form.

• The cross-barred form, al-kāf al-maškūlah or al-kāf al-mašqūqah, is the Nastaliq form used predominantly in the Perso-Arabic script and as an alternative form of the version above in all forms of Arabic. It has a particular use in the Sindhi language of Pakistan where it represents the aspirated /kʰ/ and is called keheh.

• The long s-shaped variant form, al-kāf al-mabsūṭah, which is used in Arabic texts and in Thuluth and Kufic. It is a separate letter in the Sindhi language of Pakistan, where it represents the unaspirated /k/.

• The variant of letter khe in Persian, and in Tausug with a line above named gaf is used, and it is thus written as:

Other than the four variants of the letter kāf as mentioned below, there are also five other variants of the Persian letter gaf, namely,

• the letter khe with one dot above is used in the Jawi alphabet, and it is thus written as:

• the letter kāf with three dots below is used in the Pegon alphabet, using a modified basic form of kāf, and it is thus written as:

• the letter kāf with one dot below is also used in the Pegon alphabet for writing Javanese and Sundanese in Arabic script, but is also used in the Arwi alphabet for the Tamil language to represent, and it is thus written as:

• the letter khe with a ring is used in Pashto, and it is thus written as:

• in Chechen, Kabardian, and Adyghe, the Arabic character ࢰ is used to spell or. In Chechen, ⟨گ⟩ is alternatively used as well.

In Ottoman Turkish, Chagatai, Kazakh, Kyrgyz, Azerbaijani, Uyghur, Moroccan Arabic, Xiao'erjing script, the Arabic letter ng has two forms, namely:

• the letter khe with three dots above is used, and thus it is written as:

• the basic form of the letter kāf with three dots is used, and thus it is written as:

There is also one another variant of the letter ng, which is the letter khe with three dots below, and it is thus written as:

In the Sindhi alphabet, the letter gaf with two dots above is used, and it is thus written as:

There is also letter gueh in the Sindhi alphabet. Gueh is thus written as:

Before 1928, the Nogai alphabet was written in Arabic script. There is one such letter based on a basic form of kāf with three dots below, and it is thus written as:

In varieties of Arabic kāf is almost universally pronounced as the voiceless velar plosive, but in rural Palestinian and Iraqi, it is pronounced as a voiceless postalveolar affricate.

As an affix

Prefix

In Arabic, kāf, when used as a prefix كَـ ka, functions as a comparative preposition (أداة التشبيه, such as مِثْل or شَبَه) and can carry the meaning of English words "like", "as", or "as though". For example, كَطَائِر (), means "like a bird" or "as though a bird" (as in Hebrew, above) and attached to ذٰلِك "this, that" forms the fixed expression كَذٰلِك "like so, likewise."

Possessive suffix

When adjoined at the end of a word, kāf is used as a possessive suffix for second-person singular nouns (feminine taking kāf-kasrah كِ, and masculine kāf-fatḥah كَ); for instance, كِتَاب kitāb ("book") becomes كِتَابُكَ kitābuka ("your book", where the person spoken to is masculine) كِتَابُكِ kitābuki ("your book", where the person spoken to is feminine). At the ends of sentences and often in conversation the final vowel is suppressed, and thus كِتَابُك kitābuk ("your book"). In several varieties of vernacular Arabic, however, the kāf with no harakat is the standard second-person possessive, with the literary Arabic harakah shifted to the letter before the kāf: thus masculine "your book" in these varieties is كِتَابَك kitābak and feminine "your book" كِتَابِك kitābik.

The Hebrew letter Kaf (Hebrew: כַּף, romanized: kap̄) represents the phonemes /k/ and /x/. The former value /k/ is common for all pronunciations of Hebrew and is pronounced [k], while the latter /x/ is classically pronounced as the former's fricative counterpart [x]. It shifted to be pronounced [χ] in some traditions, notably in Ashkenazi Hebrew and by extension, most speakers of Israeli Hebrew.

Orthographic variants
Various print fonts			Cursive Hebrew	Solitreo	Rashi script
Serif	Sans-serif	Monospaced
כ	כ	כ

The letter has two pronunciations — one plosive /k/ and its fricative counterpart /x/, making it a begadkefat letter. A dagesh qal (dot) written in the letter represents that the plosive value should be taken; The lack thereof — the fricative.

The letter must be written a different way when it appears at the end of a word. This variant is called "Final Kaf/Chaf" or "Kaf/Chaf Sofith".

Significance of kaf in Hebrew

In gematria, kaf represents the number 20. Its final form represents 500, but this is rarely used, taw and qof (400+100) being used instead.

As a prefix, kaf is a preposition:

• It can mean "like" or "as", as in literary Arabic (see above).
• In colloquial Hebrew, kaph and shin together have the meaning of "when". This is a contraction of כַּאֲשֶׁר, ka'asher (when).