12 p.m. is noon

19.11.17: engl/12pm is noon:
. the way to see that 12 p.m. is noon
rather than midnight;
is to realize that 12 on the clock
is actually the clock's name for 0;
and, 0pm is the start of pm (afternoon),
so 12pm is noon.

11.22: wiki agrees:
Noon (or noon time) is written as
12 p.m. (for post meridiem) or 12 pm.

wiki page for this issue:
official Confusion_at_noon_and_midnight

The American Heritage Dictionary of the English Language
states "By convention, 12 PM denotes noon.
Because of the potential for confusion,
it is advisable to use 12 noon and 12 midnight."
The NIST website states that "12 a.m. and 12 p.m.
are ambiguous and should not be used."

and the reason for this confusion?
. usa's official style manual of the Gov Printing Office
changed its mind!
. it used 12 a.m. for noon and 12 p.m. for midnight
until its 2008 edition
when it reversed these designations/
(so the current version agrees with me:)

GPO Style Manual 2016:
. the 2016 edition of the GPO Style Manual is the
first revision to be issued under GPO's new name,
U.S. Government Publishing Office.
Since 1894, the GPO Style Manual has served as
a guide to the style and form of
Federal Government printing and publishing.
The Manual has come to be widely recognized by
writers and editors both within and outside the Federal Government
as an important editorial tool.

manl intro:
. the Director of the U.S. Government Publishing Office
is authorized to determine the form and style
of Government printing.
The Style Manual is the product of
many years of public printing experience,
and its rules are based on principles of good usage
and custom in the printing trade. Essentially,
the Style Manual is a standardization device
designed to achieve uniform
word and type treatment,
and aiming for economy of word use.
The Style Manual has served
Federal printers since 1894,
and with each new edition,
the traditions of printing and graphic arts
are carried forward into new technologies.

the 2016 manl, p236:
"References to meridian in statements of time
are abbreviated as follows:
12 p.m. (12 noon)
12 a.m. (12 midnight)."