There's a question on English Language Learners that's been making the rounds recently, it's been on the Hot Network Questions list since January 5 this year and has attracted something like 36,000 views (all credit to tchrist's exhaustive and flawless answer for this extraordinary phenomenon).
I posted an answer, and from a comment, it seems I've done something terribly wrong, but I don't understand what exactly.
Until January 5, I believed that PM, P.M., p.m. or pm was short for post meridian and that it was spelled as two separate words. That's how I've always pronounced it. but it was pointed out to me that the correct Latin spelling is post meridiem. So, I edit the post and add the following reflection
… in English spelled postmeridian [emphasis mine].
Shortly after, a user posted the following comment
'Postmeridian' (single word, no space) may be English (although it is certainly antiquated by 'afternoon') but 'P.M.' is an abbreviation for the Latin phrase 'post meridiem'. There is no 'English spelling' of Latin phrases, there are only translations, but even then 'postmeridian' is actually worse of a translation than 'after noon', because of its archaic status. […]
Was I that wrong to say that ‘post meridiem’ is spelled ‘postmeridian’ in English? Is postmeridian an English translation? That doesn't make much sense to me, it looks very much like a loanword that's been anglicized (?) not translated.
The following definitions are from Merriam-Webster
post meridiem
adjective : being after noon —abbreviation PM
First Known Use: 1647
postmeridian
adjective : occurring after noon : of or relating to the afternoon the postmeridian hours of the day
Origin and Etymology
Latin postmeridianus, from post- + meridianus meridian
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Can someone explain if the original Latin expression consists two words and is spelled “post meridiem”, why is it spelled as a single word in English with a different suffix, dian, postmeridian?
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Is postmeridian (or post meridian) a bastardization?
- What is the history of the word postmeridian and its spelling?
Related (paullum) What is the proper name for "AM" and "PM"?
Best Answer
There was a (post-classical) Latin word postmeridianum from the 6ᵗʰ century that meant “after midday” which English first borrowed directly as postmeridian no later than 1583.
The OED says this of its history:
The word postmeridian is now mainly used as an adjective:
It also clocks in as a rare noun meaning
Here’s one citation for that use:
The word is also sometimes used as an adverb meaning in or during the afternoon. For example: