From Offset

Numero sign

History and conventions

I believe in English we inherited the abbreviation "No" for numero from some other language. More research is needed. Nowadays, when we write it and read it, it means "number". It's just like how we use "lb" to mean "pound", even though it's really an abbreviation of libro or whatever.

In English and other European languages we have a custom of writing abbreviations with leading letters at their regular size, and then we omit some letters, and then we put one or more ending letters in tiny superscript. If we don't use superscript, we might put a period at the end, like in "Mrs." or "No.". In English we might uadd an apostrophe to represent missing letters, but this is usually only done with certain words, like "rock 'n' roll".

Why do we call "No" numero sign? I don't know. I'm guessing it's because when we're using "No" to mean "number", we always keep the "N" and "o" together; we wouldn't split it with a hyphen if we were out of room on a line. Thus, it's convenient to think of the two glyphs together as being a single symbol: the numero sign. Just a guess though.

Actual numero signs

This is a typical numero sign: capital letter "N" adjacent to a superscript letter "o". The "o" is usually fairly small:

N^o

The "o" can optionally be underlined:

N^o

The "o" may be vertically positioned such that it's top edge is well above the caps-height of the "N":

N^o

or a bit below:

N^o

Unicode has a numero sign character. It's intended for use only in Cyrillic text (e.g., as used in Russian, not Western European languages), and to provide backward compatibility with some East Asian character sets that had such a symbol. It usually has a line under the "o", and the "o" is positioned directly such that it's mid-height matches the "N"'s mid-height:

№

In serif fonts, the Cyrillic numero sign's "N" might be very curly, not matching the serif style of a regular capital "N", and the "o" might likewise be a little more decorative than usual. Here's how it looks in your browser's default serif font:

№