Time--A guest blog by Larry Kellerman

The following is from an email sent by Larry Kellerman, Librarian at Central Lakes College. The email was sent on December 16, 2008 to faculty and staff at the college. The following is used with his permission.


The topic is time. This is an academic institution where we teach English grammar. Yet, one particular grammatical error shows up in much of what we post on the walls and in other documents. The time. More examples later. First some facts:
Meridian means “noon" (mid-day).
Anti- means “before.”
Post means “after.”

Anti-Meridian abbreviated is “a.m.” (lower case a, period, lower case m, period.)
Post-Meridian abbreviated is “p.m.” (lower case p., period, lower case m. period.)
Capital “A.M.” mean amplitude modulation (great sound).
Capital “P.M.” means Prime Minister. Also used for Post Master, Provost Marshall and Past Master (of a lodge).
Lower case “am” without periods is a form of “to be.” I am …
Lower case “pm” has no meaning.

The number and the colon have different meanings if the a.m. or p.m. are not included.
9:18 could be a ratio of 3:6 or 1:2.
9:18 a.m. is a specific time of morning.
9:18 am is a ratio of who you are.
9:00 (with the double zeros) is also important. It indicates “o’clock.”

The hour number without the double zeros, but with a.m. or p.m. is also acceptable, but less specific.
Without the period, 9 am could mean “9 am going to do something.” Also bad grammar.
(All of the above is based on the O.E.D. (that’s the Oxford English Dictionary).