Gwillim Law wrote:
I don't see any solecism. The superscript o is not an ordinal indicator here. Nº is not a synonym for Nth. The words that are abbreviated Nº are masculine nouns: French numéro, Spanish número, Italian numero, etc.
Perhaps I'm being pedantic, but I think º (U+00BA MASCULINE ORDINAL INDICATOR) should be used only with ordinals. I know ordinal indicators are sometimes used elsewhere (e.g., "M.ª" for "Maria" in Portuguese, "Nº" for "Number" in English) but these should really be superscript letters and using ordinal indicators can lead to inconsistencies. For example, the Portuguese abbreviation for "Excelentíssimo" is "Ex." followed by superscript "mo" and no ordinal indicator looks like superscript "m" so people typically either use superscript "mo" or don't bother with superscripting and just write "Ex.mo", and this is inconsistent with using an ordinal indicator to abbreviate "Maria".