Full Form of AM and PM: AM PM Meaning
Full
Form of AM and PM :
AM
– Ante Meridiem (which means ‘before mid-day’)
PM
– Post Meridiem (which means ‘after mid-day’)
AM
and PM Full Form are Ante Meridiem (‘before
mid-day’) and Post Meridiem (‘after mid-day’). The 24 hours in a day is
divided into two parts – AM and PM. In other words, Ante Meridiem represents
‘midnight to noon’ and Post Meridiem represents ‘Noon to Midnight’. The terms
are derived from Latin words where ‘meridies’ means ‘midday’; ‘ante’ means
‘before’; and ‘post’ means ‘after’.
Also, most people tend to get confused with the
usage of AM and PM for 12 O’ clock. Since the word ‘meridiem’ refers strictly
to noon or midday, the term AM and PM does not apply for 12:00. The time 12:00
has to be used without any suffix. It is either 12:00 or 12:00 midnight in a
12-hour clock.
Full Form of AM and PM – Additional Information
Time is an interesting mystery, which we have,
for our own convenience, described it in terms of mathematics, physics, and
clocks. While we have yet not clinched any strong evidence as to what exactly
time is; whether it is a just a figment of imagination or has something way
murkier behind its existence. Whatever the case may be, time remains, at least
for now, an oblivion case.
Like I have mentioned before, clocks are one of
the methods by which we define time. It is reasonable, of course, because not
every human being is a mathematics or science genius to fashion his or her
vocabulary with technical words. Keeping beside the general stuff, which we
shall anyway have in our consideration throughout the discussion, let us begin
with some preliminary information that everyone must have.
We shall keep our focus particularly on the
format of time. We shall begin with the 6-hour time format followed by 24-hour
time format briefly followed by an extensive discussion of our main theme,
which is a 12-hour format that comprises two essential components namely, AM
that stands for Ante Meridian and PM that stands for Post Meridian. Let us
explore Full Form of AM and PM
Before we move to 24-hour format, we shall
discuss the now archaic system of time, 6-hour clock system. The system is a
traditional system of time that is prevalent in the Thai language. It was
formerly used in languages like the Lao language and the Khmer language. Though
like the 24-hour clock system it counts 24 hours every day but the time period
is divided into four quarters. For each quarter, the number of hours counted is
six.
Barring the sixth hour in every quarter, the
hours in each quarter are indicated in period denominated words, which are mong
chao that indicates the first half of the day (from 7.00 to 12.59); Bai … mong
that indicates latter half of the day (from 13.00 to 18.59); … thum
that indicates the first half of the night; Ti … that indicates
the latter half of the night time. These terms have been believed to have
originated from the sounds produced by the conventional time keeping
inventories.
People used to play the gong when the hours in
day were announced whereas the drum was played to announce hours in night time.
This explains the term mong, which is similar to the sound of the gong
and thum, which is similar to the sound produced by the drum. In Thai,
the word Ti is used to indicate the hit and is believed to
have come from the activity of hitting the time keeping inventories. Morning
and evening are indicated by the words Chao and bai
respectively.
Now the exception, which is the sixth hour of
each quarter is indicated by different terms. At dawn, the sixth hour of the
quarter is referred to as yam rung whereas the sixth hour at the dusk
is referred to as yam kham. Kham and rung mean dusk
and dawn respectively. The time of midday and midnight is referred to as thiang/thiang
wan and thiang khuen respectively. Both of these terms regionally
mean midday and midnight. . Let us explore Full Form of AM and PM.
This system of time has been used since the time
of Ayutthaya Kingdom however, it was codified in the year 1901 by King
Chulalongkorn. It was codified in Royal Gazette 17:206. Now, the use of these
terms and the time format is limited to colloquial use.This system was
eventually abolished in Laos and Cambodia during the French intervention and
the French system of the time was then used.
Of the two standard time conventions in the
world, the 24-hour format is one of them. It is the time convention wherein the
day occurs from midnight to midnight. The time format is, as its name suggests,
divided into 24 hours. The time in this convention is indicated in hours, which
have been passed since midnight. That is from 0 hours to 23 hours. This system
is a comparatively popular time notation in the world as of now.
The time convention is used by an international
standard by the name ISO 8601, which is an international standard that covers
the transmission of date and time data and is issued by the International
Organization for Standardization (abbreviated as ISO). The 24-hour format is
used in medical field for documenting care that prevents any confusion as to
the events pertaining to the medical history of a patient. This standard of
time is commonly known as Military Time in countries like Canada, India, the
United States and other countries where the 12-hour format is still prevalent.
. Let us further explore AM and PM Full Form.
Now that we have discussed the 24-hour format, we
shall move closer to our main discussion on the less popular 12-hour format.
12-hour time format is one of two prevalent standard time conventions in the
world in which the time (24 hours in a day) is bifurcated into two periods.
Those two periods are AM, which as mentioned above stands for Ante Meridian,
and PM, which stands for Post-meridian. The former expression is a Latin
phrase, which means before midday and the latter expression, which is obviously
another Latin phrase, stands for after midday.
In this system of time, each period comprises 12
numbers, in which the number 12 functions as a zero, followed by 1, 2, 3, and
so on until 11 in a sequential order. The time cycle begins from 12 midnight
(12 a.m.) and continues to 12 noon, which is understood by 12 p.m. and then
continues to the midnight to mark the end of the day.
Let us explore the history behind the development
and use of this kind of time format. The origins of the 12-hour clock format
can be found in ancient civilizations like Egyptian and Mesopotamian, which are
known to have ushered in a new age of human development. Ancient Egyptian
civilization is known to have developed many inventories like sundials that were
for day time usage and water clocks that were night time usages. These
inventories have been found in various Egyptian tombs and even that of the tomb
of Amenhotep, who was a renowned Pharaoh. These inventories or let us call them
clocks used to divide time into 12 hours, much like the modern 12-hour clock
system.
The great Roman empire too had used the system of
12-hour clocks. The daylight was bifurcated into 12 hours though there may be
variations in a year and the night was bifurcated into four watches. Even
though there were differences in the then and now prevalent system, the fundamentals
were pretty much similar.
The world witnessed the first mechanical clock
during the 14th century. Many civilizations used dials that
presented all 24 hours, however, in areas in and around Northern Europe dials
used indicated all 12 hours based on Roman Numerals. This system of using Roman
numerals for indicating hours is known as Double XII system and could be seen
in some clocks these days. The system of 12-hour clock was used for quite a
substantial time of British empire.
In the 15th century, this system of
12-hour clock became a standard for indication of time in the British empire,
particularly in Northern Europe. The use of the 24-hour system was reserved for
special uses such as in chronometers and astronomical clocks. Today most analog
clocks use the 12-hour system, which is more convenient for such types of
clocks. Let us further explore AM and PM Full Form
The use of 12-hour clock system and 24-hour clock
system varies. For example, many countries use the 12-hour clock system in
spoken system whereas the 24-hour clock system is used for the written system.
What’s more interesting that non-English speaking countries might not even know
what a.m. and p.m. stand for and what their respective uses are. The same goes
for use in computer systems. The default time format in most of the operating
systems is the 24-hour time format however, one can change it to 12-hour format
as per one’s convenience.
Now that we have dealt with 12-hour format in
general, let us discuss two important components of this category of format.
These two components, AM and PM have great importance in the 12 hour system and
therefore, must be understood properly. Once you have understood these
terminologies then the purpose and functioning of the 12-hour system would be a
piece of cake for many to understand.
AM – Ante Meridian (Before Noon) and PM – Post Meridian (After Noon):
These two must be understood together and
therefore, will be dealt with under the same head. Both terms a.m. and p.m. are
abbreviated forms of Latin phrases namely, ante meridian and post meridian
respectively. These two phrases mean before noon and after noon in English and
have relevance as far as the 12-hour clock system is concerned. These terms are
also written as AM and PM and am and pm. They are more commonly known in
Spanish and English language. In Greek, they are used
as π.µ. and µ.µ. respectively. It is rare to see people using
the formal expressions that are “before noon” and “after noon”, as most of the
use of 12-hour clock is verbal only.
Now let us discuss the typographical aspects of
both these terms. As mentioned earlier that there many abbreviated variants to
say ante meridian and post meridian like a.m., p.m., AM, PM, and whatnot, there
are still debates on which one is correct. Many books prefer the use of space
between the number and the abbreviated forms a.m. and p.m. Many stylebooks
suggest that if not suggesting any numeric, then do not use a.m. and p.m. The
typography will largely vary with different countries. Thus, one has to adjust
with the country usage. Let us explore more about Full Form of AM and
PM
There is a lot of confusion regarding the use of
both these abbreviated terms a.m. and p.m. Many people find it confusing as far
as what time 12 p.m. and 12 a.m. suggest. Literally speaking, noon is neither
before or after, as the full forms of a.m. and p.m. suggest. Thus, technically,
a.m. and p.m. do not apply. To sort out this confusion, the American Heritage
Dictionary of the English Language (abbreviated as AHD), which is an American
Dictionary that Houghton Mifflin publishes, has appended a note on this issue,
which says and I quote “By convention, 12 AM denotes
midnight and 12 PM denotes noon.
Because of the potential for confusion, it is
advisable to use 12 noon and 12 midnight.”
There are other interpretations made by other persons and institutions as well.
In the book Mapping Time, the author E.G. Richards gave a diagram
suggesting that 12 a.m. indicates noon and 12 p.m. indicates midnight. This
interpretation is quite contrary to the common use.
Many American style books and Frequently Asked
Questions (abbreviated as FAQs) on the webpage of the National Institute of
Standards and Technology (abbreviated as NIST) suggest that one should use noon
or 12 noon and midnight or 12 midnight to avoid confusion because there is no
definite answer to the question raised. So, avoid using 12 a.m. and 12 p.m. The
same is recommended by the Canadian Press Stylebook, which in its 11th
edition published in the year 1999 states that it is advisable to write 12 noon
or 12 midnight instead of 12 a.m. and 12 p.m.
The FAQs on the webpage of the Britain’s National
Physical Laboratory mentions that unless there is any option, it is recommended
that the use of the terms 12 a.m. and 12 p.m. should be avoided. The issue is
contentious and has not been resolved. Many American style books have developed
this method of referring to both these time periods as 11.59 p.m. and 12.01
a.m. This is becoming increasingly common in American legal system, particularly
in contracts and for announcing schedules for trains, airplanes, buses, etc.
This problem does not arise when the time format
is used is 24-hour time format. This category of 24 hour format because it uses
00.00 for indicating midnight at the beginning of the day and 12:00 is used for
indicating noon. In fact in the 24-hour time format, 24:00 can be very
conveniently used indicate midnight at the day’s end.
In the United Kingdom many methods have been
developed to alleviate the confusion in the use of these terms. Take for
example TV mag, Sun newspaper from the date December 17, 2005 makes
use of noon for 12.00 and midnight for 0.00. The sequential enumeration begins
with a.m. and p.m. but these have not been used again. Sometimes, one can see
use of 12 midnight in sub-listings. Daily Telegraph, London’s prominent
newspaper, makes use of the terms “12.00 noon” and “12.00 midnight” in its
respective individual listings.