You all know that quotation marks (“little goose feet” if you’re a grade schooler in Germany) are used to indicate that you’re repeating exactly what someone says (or writes).
We have another use, in the typography trade, called “scare quotes.” They’re used to separate something from its context. You just saw two sets of scare quotes in this post, so far.
Another use just occurred to me: to indicate how to pronounce something. Here’s my example:
The only exceptions are single polygons larger than a triangle, and something called the θ0 (“theta zero”) graph, in which a vertex in the center of a hexagon is connected to two opposite vertices.
https://www.quantamagazine.org/a-childs-puzzle-has-helped-unlock-the-secrets-of-magnetism-20190124
If they hadn’t said otherwise, I’d have pronounced it “theta sub zero.”
I think I run into this use mostly in subjects that are somewhat abstruse, such as some mathematics and physics. The sentence is in an article about the atomic structure of magnetism. Go follow the link if you’re interested.
So there you have it. Make sense?