Nun is the fourteenth letter of many Semitic abjad

Abjad

An abjad is a type of writing system in which each symbol always or usually stands for a consonant; the reader must supply the appropriate vowel....

s, including Phoenician, Aramaic

Aramaic language

Aramaic is a group of languages belonging to the Afroasiatic language phylum. The name of the language is based on the name of Aram, an ancient region in central Syria. Within this family, Aramaic belongs to the Semitic family, and more specifically, is a part of the Northwest Semitic subfamily,...

, Hebrew

Hebrew language

Hebrew is a Semitic language of the Afroasiatic language family. Culturally, is it considered by Jews and other religious groups as the language of the Jewish people, though other Jewish languages had originated among diaspora Jews, and the Hebrew language is also used by non-Jewish groups, such...

  and Arabic alphabet

Arabic alphabet

The Arabic alphabet or Arabic abjad is the Arabic script as it is codified for writing the Arabic language. It is written from right to left, in a cursive style, and includes 28 letters. Because letters usually stand for consonants, it is classified as an abjad.-Consonants:The Arabic alphabet has...

  (in abjadi order). It is the third letter in Thaana

Thaana

Thaana, Taana or Tāna is the modern writing system of the Divehi language spoken in the Maldives. Taana has characteristics of both an abugida and a true alphabet , with consonants derived from indigenous and Arabic numerals, and vowels derived from the vowel diacritics of the Arabic abjad...

 , pronounced as "noonu". Its sound value is n.

The Phoenician letter gave rise to the Greek

Greek alphabet

The Greek alphabet is the script that has been used to write the Greek language since at least 730 BC . The alphabet in its classical and modern form consists of 24 letters ordered in sequence from alpha to omega...

 nu

Nu (letter)

Nu , is the 13th letter of the Greek alphabet. In the system of Greek numerals it has a value of 50...

 (Ν), Etruscan  , Latin

Latin alphabet

The Latin alphabet, also called the Roman alphabet, is the most recognized alphabet used in the world today. It evolved from a western variety of the Greek alphabet called the Cumaean alphabet, which was adopted and modified by the Etruscans who ruled early Rome...

 N

N

N is the fourteenth letter in the basic modern Latin alphabet.- History of the forms :One of the most common hieroglyphs, snake, was used in Egyptian writing to stand for a sound like English ⟨J⟩, because the Egyptian word for "snake" was djet...

, and Cyrillic

Cyrillic alphabet

The Cyrillic script or azbuka is an alphabetic writing system developed in the First Bulgarian Empire during the 10th century AD at the Preslav Literary School...

 Н.
Nun (Hebrew: נ) is thought to have come from a pictogram of a snake (the Hebrew word for snake, nachash begins with a Nun and snake in Aramaic is nun) or eel.