Meanings
bya1
symbol
- Abbreviation of billion years ago (A symbol for a unit of measure.)
- usuallySynonym of Gya (“billion years ago (short scale): 10⁹ years ago”).
1 more example
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.
2015, Joyce A. Quinn, Susan L. Woodward, “Introduction”, in Earth's Landscape: An Encyclopedia of the World's Geographic Features, volumes I: A–L, Santa Barbara, CA: ABC-CLIO, →ISBN, page xxxiSynonyms: Gya
- dateduncommonbillion years ago (long scale):10¹² years ago: a trillion years ago (short scale).
Bya2
symbol
- Alternative spelling of bya (“billion years ago”).
- alternativedateduncommonAlternative spelling of bya (“billion years ago (long scale):10¹² years ago: a trillion years ago (short scale)”).
BYA3
Synonyms & antonyms
symbolSynonym of Gya (“billion years ago (short scale): 10⁹ years ago”).
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Cite this entry
APA
bya. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/bya
MLA
“bya.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/bya. Accessed November 2, 2026.
Chicago
WatkinsX Dictionary, s.v. “bya,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/bya.
Source: bya on Wiktionary, CC BY-SA 4.0.