Definition

1. Adverb:

   • Before noon: Used to specify that a time occurs in the morning, between midnight (12:00 a.m.) and noon (12:00 p.m.).
   • In the forenoon: Denotes the period of the day from midnight until midday.

2. Adjective:

   • Of or relating to the period from midnight to noon: Describes something that occurs in the morning hours.

Usage Examples

• Adverb:

  • The meeting is scheduled for 10:30 ante meridiem. (The meeting is scheduled for 10:30 in the morning.)
  • The store opens at 9 ante meridiem. (The store opens at 9 a.m.)

• Adjective:

  • Please note the ante meridiem hours of operation. (Please note the morning hours of operation.)
  • The ante meridiem flight is often less crowded. (The morning flight is often less crowded.)

Advanced Usage

• Formal and Technical Contexts: "Ante meridiem" is the full Latin form, often used in formal, legal, or technical writing. In everyday usage, the abbreviation "a.m." is almost universally preferred.

  • The contract stipulates delivery by 11:59 ante meridiem. (The contract stipulates delivery by 11:59 a.m.)

• Clarification with 12:00: "12:00 a.m." specifically refers to midnight, the start of the day.

  • The event begins at 12:00 ante meridiem (midnight).

Variants and Related Words

• a.m. (also A.M.): The standard abbreviation for "ante meridiem."

  • Let's meet at 11 a.m.

• Post Meridiem (p.m.): The counterpart meaning "after noon."

  • The afternoon session starts at 2 p.m.

Synonyms

• Before noon
• In the morning
• Forenoon (archaic or formal)

Notes on Usage

• Capitalization: The abbreviation is commonly written in lowercase ("a.m.") or uppercase ("A.M."). Both are acceptable, but consistency within a document is key.
• Punctuation: In American English, periods are typically used in the abbreviation (a.m.). In British English, they are often omitted (am).
• With "o'clock": It is redundant to use "a.m." or "p.m." with "o'clock." Use one or the other.
  • Correct: 7 a.m. or seven o'clock in the morning.
  • Incorrect: 7 a.m. o'clock.

Adjective

1. before noon

Adverb

1. before noon
   • let's meet at 11 A.M.