# mega-annum

> English word · Noun · IPA /ˌmɛɡəˈænəm/

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

## Etymology
From mega- + annum.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/mega-annum