Ordinal Indicator - Similar Conventions

Similar Conventions

Some languages use superior letters as a typographic convention for abbreviations that aren't related to ordinal numbers – the letters o and a may be among those used, but they don't indicate ordinals:

Spanish uses the indicator letters in some abbreviations, such as Vº Bº for visto bueno ("approved"); and Mª for Maria, a Spanish name frequently used in compounds like José Mª.

In Portuguese, the underlined "º" and "ª" are used with many abbreviations, and should be preceded by a period. In fact, there is no limit for which words may be abbreviated this way. Sometimes, other letters are also written before the "º" or "ª". For example: Ex.mo for Excelentíssimo (an honorific), L.da for Limitada (Ltd.), Sr.a for Senhora (Ms.), etc.

English has borrowed the "No." abbreviation from the Romance languages word numero (according to the OED, the term is from the Latin numero, which is the ablative form of the word numerus ("number"). Similar forms exist as the word for "number" is derived in other Romance languages: numero in Italian, numéro in French, and número in Spanish and Portuguese), applying it as an abbreviation for the English word "number". This is sometimes written as "Nº", with the superscript o optionally underlined; see numero sign.

Use of the ordinal-indicating Unicode characters for these kinds of abbreviations is a matter of preference, but can be misleading; the "º" in "Nº", for example, is not intended to indicate ordinality at all.