I remember often having professors in college use degree symbols to write shorthand versions of Latinate ordinal numbers.

For example:

1°    Primary
2°    Secondary
3°    Tertiary
4°    Quaternary

I have a few questions regarding this shorthand approach:

  1. Does this approach have a name?

  2. What is the origin of this approach?

  3. Is it simply a shorthand developed by professors or is it more widely used?

I thought I'd gain insight by exploring the use of superscript primes in the sciences, but I didn't find answers to my questions via that rabbit hole adventure...

  • 2
    Maybe the o up there is actually part of the word represented. 1° is "primo", 2° is "secundo", etc.
    – GEdgar
    Commented Oct 18, 2018 at 14:47
  • Something along the lines perhaps of the old-fashioned paper sizing: 4vo quarto, 8vo octavo, &c.?
    – JDF
    Commented Oct 18, 2018 at 14:56
  • Possible duplicates -- and a bit wider in scope, giving the correct answer not just for the degree symbol but all the ordinal indicators such as "st", "nd", and th": english.stackexchange.com/questions/35310, english.stackexchange.com/questions/192804
    – MetaEd
    Commented Oct 18, 2018 at 20:32

2 Answers 2


This is an ordinal indicator.

In written languages, an ordinal indicator is a character, or group of characters, following a numeral denoting that it is an ordinal number, rather than a cardinal number.

In English orthography, this corresponds to the suffixes -st, -nd, -rd, -th in written ordinals (represented either on the line 1st, 2nd, 3rd, 4th or as superscript, 1st, 2nd, 3rd, 4th)... [and] ... different characters from the superscript lower-case letter o or a, the degree symbol (°), or the ring diacritic (˚).


Wikipedia further states. regarding origin :

The practice of indicating ordinals with superscript suffixes may originate with the practice of writing a superscript o to indicate a Latin ablative in pre-modern scribal practice.

The word 'ordinal' distinguishes it from the usual way of writing numbers which is 'cardinal'.

Cardinal number n. (Arith.): a number which answers the question ‘how many?’; one of the primitive or ‘natural’ numbers


Ordinal Marking position in an order or series; applied to those numbers which refer something to a certain place in a series


  • 3
    I wasn't actually expecting such a simple or straightforward answer given how little turned up with a Google search. This is exactly what I was looking for! Thanks, Nigel! Commented Oct 18, 2018 at 14:40

You see it more in Spanish speaking countries. Their masculine (and pseudo-neutral) ordinal expressions all end in "o". For example: primero, segundo, tercero, cuarto etc... Conveniently abbreviated "1°,2°,3°,4°...etc." Note that it would end in "a" if the counting suffix is conjugated to the feminine form. Perhaps that is the origin. A suggestive name for the approach might be 'Spanish ordinal numbers'. At any rate, it looks like that is a searchable term.

  • Spanish or Italian. —And in French most ordinals are abbreviated with superscript e, from the suffix –ième. Commented Nov 27, 2023 at 21:19

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