Noun. Description of the state of times before or after noon in the 12-hour clock. Can be either ante meridiem (A.M.) or post meridiem (P.M.)The term meridiemem was first defined and used in Chicago, on Oct. 20th 2011 by Benjamin Michael Brown, Piotr Bieszk, and Shavar Beckford.
Q: Which meridiemem describes the time before noon?
A: The “AM” meridiemem describes times before noon. The meridiemem “PM” describes times after noon.