[Tex2002ans]

Originally Posted by enuddleyarbl

Usually, when I see A.M. and P.M. in books, they've got something like class="small" or class="smallcaps" around them. Out of curiosity, does anyone know why? I never see things like U.S., D.C. or L.A. "classed" like that. Why A.M. and P.M.?

Like others said, some Style Guides put acronyms in smallcaps or "shrunken caps":

<p>The <small>FBI</small> said he was shot at 8:00 <span class="smallcaps">am</span> in 2020 <small>AD</small>.</p>

It's a very poor idea in ebooks though...

Should be replaced with simple ALL CAPS:

<p>The FBI said he was shot at 8:00 AM in 2020 AD.</p>

- - -

Note: I believe we discussed this smallcaps/acronym stuff + all the pros/cons in extreme detail:

• 2022: "How do I get rid of Table of Contents?"
• 2022: "CSS to Approximate a Telegram?"
  
  • (I believe this Telegram topic was even yours!)
    
• 2020: "Alternate glyph support (font-variant-alternates)"
• 2021: "RegEx: Insert nbs between initials, etc."

If you type this into your favorite search engine:

smallcaps Tex2002ans site:mobileread.com

or:

acronyms Tex2002ans site:mobileread.com

you can find lots of previous discussion.

Originally Posted by enuddleyarbl

And, while I'm asking silly questions, is there a special character replacement that ought to be used in place of the abbreviations?

I find SQUARE PM (U+33D8) for p.m., but nothing for a.m..

EDIT: I found the a.m. equivalent "SQUARE AM (U+33C2)".

No. I would not use those at all.

Those are a part of the "CJK Compatibility" block, and are only meant for usage in some Chinese/Japanese/Korean (etc.) texts.

I wrote a bit about that a few months ago in:

• /r/LibreOffice: "Encircled Alphanumeric"

which described the CJK circled number characters like:

• ① = U+2460 = CIRCLED DIGIT ONE
• ㊿ = U+32BF = CIRCLED NUMBER FIFTY