英和和英

略号

mya

1. million years ago: megayears ago.

   Alternative forms: Mya, MYA

   Coordinate terms: kya, KYA, bya, BYA, bya, BYA, bya, BYA, Gya, gya, GYA

   • 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 xxxi:

     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.

語源

From Ancient Greek μύα (múa).