Meanings
plural meridiems
- rareuncountableMidday, noon.
Quantities and frequencies are distributed as follows (neglecting the meridiem hour):[…]
1919, J. R. Sutton, “A Lunar Period in the Rates of Evaporation and Rainfall?”, in Transactions of the Royal Society of South Africa, volumes VII (1918–19), Cape Town: the Society, page 1084 more examples
The same female number 1 introduced inside the ice-box at 9 a.m., to 9:15 was in lethargy, pick up and put it inside the stove to 350 degrees, to 12 meridiem, was in excellent conditions.
1983, David R. Iriarte, Scientific Works, →ISBN, page 15I wrote that the habit of schedulers in the railroad business of skipping the meridiem (they go from 11:59 a.m. to 12:01 p.m. in a split second) “. . . begs the question of what to designate the mass transit of the meridiem.”
1986–8, William Safire, Coming to Terms, Doubleday, published 1991, page 26But when the sky had brightened for the meridiem—the two to three hours of dull yet hazardous sunlight that filtered through the thick cloud cover each planetary rotation—she’d had to retire underground, losing time.
2011, Guillermo Del Toro, Chuck Hogan, The Night Eternal (book III of The Strain Trilogy), William Morrow, →ISBN, page 14From prior to first light to the meridiem – yes, that means noon – the activities around Leelanau are as varied as the people who call it home:
2022 June 20, Ross Boissoneau, “It’s A Good Morning In The County”, in The Ticker - countablecomputingThe property of a timestamp of being either a.m. or p.m.
if (hour < 12) { meridiem = 'am'; } else { meridiem = 'pm'; }
2008 July, David Sawyer McFarland, “Working with Words, Numbers, and Dates”, in JavaScript: The Missing Manual, Pogue Press, →ISBN, part one (Getting Started with JavaScript), chapter section “Dates and Times”, subsection “Getting the Time”, page 1435 more examples
The terminal responds N HH MM CR where N, HH, and MM are the meridiem, hour, and minutes, as above.
1986 March, “Operation”, in Ampex 230 plus: Video Display Terminal: Operation Manual, section 10 (Setting the Time), page 3-42If a 12-hour clock is specified, the eighth field (the meridiem indicator) is required.[…]If this input string is entered, the parse still recognizes “feb” as the month name and “am” as the meridiem indicator, even though the format string specified both of these fields as uppercase, and the month name as unabbreviated.
1994 March, “System Time Operations”, in OpenVMS Programming Concepts Manual, Maynard, Mass.: Digital Equipment Corporation, section 6 (Date/Time Formatting Routines), subsection 2 (Selecting a Format), subsubsection 3 (Specifying Input Formats at Run Time), pages 5–25To the right of the radio buttons, complete the Start Time and End Time fields and select the meridiem from the AM/PM menu to define the time during which the schedule is in effect.
2014 December, “Customize Firewall Protection”, in ProSAFE Dual WAN Gigabit SSL VPN Firewall: Model FVS336Gv3: Reference Manual, Netgear, section “Manage Firewall Objects”, subsection “Define a Schedule”, page 295Ensure the meridiem (AM/PM) specification is set accordingly.
2015, “IP Environment Setup”, in STB-3000: HD Commercial Interface Set-top Box: Commercial Mode Setup Guide, LG Electronics U.S.A., Inc., section “Pro:Centric Setup”, page 56Finally, we’ll write the method to render the appointment slot radio buttons. To do this we first have to filter the slots by availabity and by whether AM or PM is selected. Both are simple checks; for the first we see if it exists in state.schedule, for the later, we check the meridiem part with moment().format('a').
2020 March 13, Tony Spiro, “Build an Appointment Scheduler Using React, Twilio and Cosmic JS”, in HackerNoon
Synonyms & antonyms
Origin
- Latinmerīdiem
- Englishmeridiem
Back-formation from the phrases ante meridiem and post meridiem (more commonly a.m. and p.m.), from Latin merīdiem, accusative of merīdiēs (“midday, noon”).
More words from Latin
Full word history & related roots →Cite this entry
meridiem. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/meridiem
“meridiem.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/meridiem. Accessed November 3, 2026.
WatkinsX Dictionary, s.v. “meridiem,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/meridiem.
Source: meridiem on Wiktionary, CC BY-SA 4.0.