Meridiem

Part of speech: noun

Definitions

1. The period of midday, typically marked by the transition from morning to afternoon
2. The specific time in a 24-hour cycle that denotes noon, often used in expressions like "a.m." and "p.m."
3. The phase of the day that occurs at twelve o'clock, dividing the morning from the afternoon

Etymology: The Latin "merīdiēs" meant "midday," literally "middle of the day," built from "medius" (middle) and "diēs" (day). In Latin, the accusative form "merīdiem" was the one that eventually reached English, but it was not the word English speakers first used for the period of midday. Instead, "meridiem" arose as a back-formation: English speakers took the phrases "ante meridiem" and "post meridiem," meaning "before midday" and "after midday," and extracted a singular noun from them. The result is a word that exists mainly because of its abbreviations. Most people encounter it only in the familiar "a.m." and "p.m." used on clocks, where the Latin phrases were shortened and the underlying noun was reconstructed from them. The Latin form that survives in English is a word that English produced from its own shorthand, rather than one it inherited directly from Latin.

Synonyms: noon, midday

Antonyms: midnight