The degree symbol is used for angles and arcs, temperatures, and the ‘proof’ of alcohol, among other things. You’ll even find it in harmonics. It started as a raised glyph of the digit 0, but best practice in typesetting and design now is to use a true degree symbol designed for the purpose.
The degree symbol is preferred because many fonts style the alternatives in ways that make them look very out of place as a degree symbol.
A non-breaking space has intentional and side benefits:
Keep digits with their unit of measurement.
Keep names from splitting over a line break.
Keep long numbers from splitting over a line break.
Identify content copied from a PDF or website.
An easily searchable character for your compositor to replace.
To Find Non-Breaking Spaces
You don’t have to rely on your eyes alone. In the Find field, type ^s to search for non-breaking spaces. You can even pair this code with wildcards to quickly add non-breaking spaces between all digits and their units of measure, or in place of simple spaces in long numbers.
Compositors and others on the design team can use the non-breaking space as a placeholder for another character, often the thin space which Word cannot produce but which makes for elegant text design.
To Type a Non-Breaking Space
On a Mac: opt + spacebar
In Windows: ctrl + shift + spacebar
Troubleshooting
It’s not just plagiarism that makes an editor look for text copied from elsewhere. The non-breaking spaces in such pasted content can really mess up layout. I see these a lot in article titles in the bibliography or reference list. By changing those to regular spaces, we can save a lot of fixing in page proofs.
To show or hide these spaces and all non-printing characters, click the ¶ icon on the home ribbon.
A non-breaking space sometimes goes by the name of a fixed space or a hard space.