Meaning of bya | Babel Free

Definitions

1. Alternative spelling of bya (“billion years ago”).
   alt-of, alternative, usually
2. Alternative spelling of bya (“billion years ago (short scale): 10⁹ years ago”).
   alt-of, alternative, usually
3. Abbreviation of billion years ago (A symbol for a unit of measure.)
   usually
4. Synonym of Gya (“billion years ago (short scale): 10⁹ years ago”).
   usually
5. Alternative spelling of bya (“billion years ago (long scale):10¹² years ago: a trillion years ago (short scale)”).
   alt-of, alternative, dated, uncommon
6. billion years ago (long scale):10¹² years ago: a trillion years ago (short scale).
   dated, uncommon

Examples

“The first (oldest) unit of time is the Precambrian Supereon, which covers much of Earth's history from its origins roughly 4.55 bya to 545 mya. Very primitive, one-celled life-forms arose as early as 4.0 bya and near the end of the era (570 mya) the oldest known fossils of multi-celled organisms appear.”

CEFR level