mega-annum

/ˌmɛɡəˈænəm/

noun

Synonym of megayear: a period of 1 million years.

“Holonyms: petasecond < giga-annum, gigayear < exasecond”

Similar
megayear
Ask AI about this wordChatGPTClaudePerplexityGoogle AIGrok

Meanings

nounmega-annum (plural mega-annums or mega-anna)

plural mega-annums · plural mega-anna

  1. Synonym of megayear: a period of 1 million years.

    Holonyms: petasecond < giga-annum, gigayear < exasecond

    1 more example

    Meronyms: quectosecond < rontosecond < yoctosecond < zeptosecond < attosecond < femtosecond < picosecond < nanosecond < microsecond < millisecond < centisecond < decisecond < second < decasecond < minute < hectosecond < kilosecond < hour < day < week < megasecond < fortnight < month < year < gigasecond < century < kiloannum, kiloyear, millennium < terasecond

    Synonyms: megayear

Synonyms & antonyms

nounSynonym of megayear: a period of 1 million years.

Similar
megayear
Also see
megayearmillionennium

Origin

From mega- + annum.

Full word history & related roots →
Cite this entry
APA

mega-annum. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/mega-annum

MLA

“mega-annum.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/mega-annum. Accessed November 3, 2026.

Chicago

WatkinsX Dictionary, s.v. “mega-annum,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/mega-annum.

Source: mega-annum on Wiktionary, CC BY-SA 4.0.