Fonts: True Type and O

Just bought Photoshop Elements 2019 and noticed that about a third of the fonts are TT, meaning True Type, and I seem to recall these fonts are the printed in the same way that they appear on the screen.

But the rest of the fonts have a slanted O in front of them.  Am unable to ascertain what this means on the internet so I thought I would try the forums.  Anybody know what this slanted O means?

Thanks,

Dan