Tsade

Tsade (also spelled ṣade, ṣādē, ṣaddi, ṣad, tzadi, sadhe, tzaddik) is the eighteenth letter of the Semitic abjads, including Phoenician ṣādē 𐤑, Hebrew ṣādī צ, Aramaic ṣāḏē 𐡑, Syriac ṣāḏē ܨ, Ge'ez ṣädäy ጸ, and Arabic ṣād ص. Its oldest phonetic value is debated, although there is a variety of pronunciations in different modern Semitic languages and their dialects. It represents the coalescence of three Proto-Semitic "emphatic consonants" in Canaanite. Arabic, which kept the phonemes separate, introduced variants of ṣād and ṭāʾ to express the three (see ḍād, ẓāʾ). In Aramaic, these emphatic consonants coalesced instead with ʿayin and ṭēt, respectively, thus Hebrew ereṣ ארץ (earth) is araʿ ארע in Aramaic.

The Phoenician letter is continued in the Greek san (Ϻ) and possibly sampi (Ϡ), and in Etruscan 𐌑 Ś. It may have inspired the form of the letter tse in the Glagolitic and Cyrillic alphabets.

The corresponding letter of the Ugaritic alphabet is 𐎕 ṣade.

The letter is named "tsadek" in Yiddish, and Hebrew speakers often give it a similar name as well. This name for the letter probably originated from a fast recitation of the alphabet (i.e., "tsadi, qoph" → "tsadiq, qoph"), influenced by the Hebrew word tzadik, meaning "righteous person".

Origins
The origin of ṣade is unclear. It may have come from a Proto-Sinaitic script based on a pictogram of a plant, perhaps a papyrus plant, or a fish hook (in Modern Hebrew, צד tsad means "[he] hunt[ed]", and in Arabic صاد ṣād means "[he] hunted").

Arabic ṣād
The letter is named ṣād and in Modern Standard Arabic is pronounced.

It is written in several ways depending in its position in the word:

Chapter 38 of the Quran is named for this letter, which begins the chapter.

The phoneme is not native to Persian, Ottoman Turkish, or Urdu, and its pronunciation in Arabic loanwords in those languages is not distinguishable from س or ث, all of which are pronounced.

Hebrew tsadi
Hebrew spelling: צָדִי or צָדֵי.

Name
In Hebrew, the letter's name is tsadi or ṣadi, depending on whether the letter is transliterated as Modern Israeli "ts" or Tiberian "ṣ". Alternatively, it can be called tsadik or ṣadik, spelled צָדִּיק, influenced by its Yiddish name tsadek and the Hebrew word tzadik.

Variations
Ṣadi, like kaph, mem, pe, and nun, has a final form, used at the end of words. Its shape changes from to.

Pronunciation
In Modern Hebrew, צ tsade represents a voiceless alveolar affricate. This is the same in Yiddish. Historically, it represented either a pharyngealized  or an affricate such as the modern Hebrew pronunciation or the Ge’ez ; which became  in Ashkenazi pronunciation. A geresh can also be placed after tsade, giving it the sound (or, in a hypercorrected pronunciation, a pharyngealized ), e.g.  chips.

Ṣade appears as amongst Yemenite Jews and other Jews from the Middle East.

Some Sephardi Jews pronounce צ like a regular s, and this is the sound value it has in Judaeo-Spanish, as in "masa" (matzo) or "sadik" (tzadik).

Significance
In gematria, ṣadi represents the number 90. Its final form represents 900, but this is rarely used, taw, taw, and qof (400+400+100) being used instead.

As an abbreviation, it stands for ṣafon, north.

Ṣadi is also one of the seven letters that receive special crowns (called tagin) when written in a Sefer Torah. See shin, ‘ayin, tet, nun, zayin, and gimmel.