Definitions

1. noun

Either of the two periods of 12 hours each on a clock face, separated by noon or midnight.

“The clock struck meridiem, signaling the start of a new day.”

2. noun

A point on a clock face, especially the points marking the hours.

“The two meridiem points on the clock face are divided by the 12-hour mark.”

3. noun

One of the two 12-hour periods of the day, especially in relation to a clock or calendar.

“The meridiem begins at 12 o’clock and ends at midnight.”