Q. I am editing an article that has sports terminology in it, and I wanted to verify whether a player’s jersey number would fall under the general rule of numbers or would be a special case in which the jersey number would be written as a numeral. And if it is to be written as a numeral, would an octothorpe/hashtag be used (for example, #24)?
A. Jersey numbers (like page numbers and a few other categories) are best expressed as numerals to reflect the way they normally appear in real life: Upon his much-anticipated return to the court, he wore number 45.* Usually, the word “number” can be spelled out; if you need to abbreviate it, we’d recommend using “No.”† instead of the number sign‡ (i.e., No. 45).
* Hint: The year was 1995, when CMOS was in its fourteenth edition.
† For the capital N, see this Q&A on a related matter (the No. 2 pencil).
‡ “Number sign” is Unicode’s name for # (U+0023); the code chart for that symbol also lists pound sign, hashtag, hash, crosshatch, and octothorpe as what it calls informative aliases (which are preceded by equals signs in the charts; see “Key to the Unicode Code Charts” at Unicode’s Help and Links page).