English edit

Alternative forms edit

Etymology edit

giga- +‎ annum

Noun edit

giga-annum (plural giga-annums)

  1. Gigayear, a billion years.
    • 2000, A. S. Weber, Nineteenth-Century Science: An Anthology, →ISBN, page 387:
      Geophysicists today estimate the earth’s age to be 4.5–4.6 Ga (giga-annums = 1 x 109 years) based on data from lead isotopes (Dalrymple 403).
    • 2014, Sophia Ahmed et al., “A Haploid System of Sex Determination in the Brown Alga Ectocarpus sp.”, in Current Biology, volume 24, number 17, →DOI:
      We report here the sequencing and genomic analysis of the SDR of Ectocarpus, a brown alga that has been evolving independently from plants, animals, and fungi for over one giga-annum.
    • 2018, Ronald Martin, Earth’s Evolving Systems: The History of Planet Earth, 2nd edition, →ISBN, page 214:
      Possible cyanobacteria from the Apex charts of western Australia, which have been dated at ~3.5 (giga-annums, or billions of years).

Translations edit