Numero sign

In English, the non-ligature form No. is typical and is often used to abbreviate the word "number".[2] (In North America, the number sign, #, is more prevalent.) The ligature form does not appear on British or American QWERTY keyboards.

The numero symbol is not in common use in France and does not appear on a standard AZERTY keyboard. Instead, the French Imprimerie nationale recommends the use of the form "n^o" (an "n" followed by a superscript lowercase "o"). The plural form "n^os" can also be used.[5] In practice, the "o" is often replaced by the degree symbol (°), which is visually similar to the superscript "o" and is easily accessible on an AZERTY keyboard.

The numero sign is not typically used in Iberian Spanish, and it is not present on standard keyboard layouts. According to the Real Academia Española[6] and the Fundéu BBVA,[7] the word número (number) is abbreviated per the Spanish typographic convention of letras voladas ("flying letters"). The first letter(s) of the word to be abbreviated are followed by a period; then, the final letter(s) of the word are written as lowercase superscripts. This gives the abbreviations n.^o (singular) and n.^os (plural). The abbreviation "no." is not used, because it might be mistaken for the Spanish word no (no, not). Furthermore, nro. and núm. are also acceptable abbreviations for número. The numero sign either as a one-character symbol (№) or composed of the letter N plus the superscript "o" character (sometimes underlined or substituted by º) is common in Latin America, where the interpolated period is sometimes not used in abbreviations.

The sign is usually replaced with the abbreviations "n." or "nº", the latter using a masculine ordinal indicator, rather than a superscript 'O'.[8]

Although the letter ⟨N⟩ is not in the Cyrillic alphabet, the numero sign № is typeset in Russian publishing, and is available on Russian computer and typewriter keyboards.

• 
  1912 typewriter with Russian layout.
  № sign can be seen on the 8 key.
• 
  Russian typewriter, circa 1985.
  № sign can be seen on the 1 key.
• 
  Russian keyboard layout for Windows.
  The № sign can be seen on the 3 key.

The № sign is sometimes used in Russia in medical prescriptions as an abbreviation for the Latin word numero to denote the number of prescribed dosages (for example, tablets or capsules), and on the price tags in drugstores and pharmacy websites to indicate number of unit doses in drug packages, although the standard abbreviation for use in prescriptions is Н. (Cyrillic 'en').

Because of more than three centuries of Spanish colonisation, the word número is found in almost all Philippine languages. 'No.' is its common notation in local languages as well as English.

"Nomor" in Indonesian and "nombor" in Malaysian; therefore "No." is commonly used as an abbreviation with standard spelling and full stop.

In some languages, Nr., nr., nr or NR is used instead, reflecting the abbreviation of the language's word for 'number'. German Nummer is represented this way, and this language capitalises all nouns and abbreviations of nouns. Lithuanian uses it as well, and it is usually capitalised in bureaucratic contexts, especially with the meaning 'reference number' (such as sutarties Nr., 'contract No.') but in other contexts it follows the usual sentence capitalisation (such as tel. nr., abbreviation for telefono numeris, 'telephone number'). It is most commonly lowercase in other languages, such as Dutch, Danish, Norwegian, Polish, Romanian, Estonian and Swedish. Some languages, such as Polish, omit the dot in abbreviations, if the last letter of the original word is present in the abbreviation.