gigayear

== English == === Etymology === From giga- +‎ year. === Noun === gigayear (plural gigayears) A billion years: a thousand million years, that is, a thousand thousand thousand years. Alternative forms: Gyr, Gy (symbols) Synonyms: giga-annum, gigaannum, Ga Holonyms: exasecond < zettasecond < yottasecond < ronnasecond < quettasecond Meronyms: quectosecond < rontosecond < yoctosecond < zeptosecond < attosecond < femtosecond < picosecond < nanosecond < microsecond < millisecond < centisecond < decisecond < second < decasecond < minute < hectosecond < kilosecond < hour < day < week < megasecond < fortnight < month < year < gigasecond < century < kiloannum, kiloyear, millennium < terasecond < mega-annum, megayear < petasecond 2002, William Harris of McMaster University in Hamilton, Canada. (quoted on Astronomy.com) It's hard to tell the difference between a 5-gigayear, 8-gigayear, and 10-gigayear cluster for such a sparse object as this unless you've got very high-quality photometry. ==== Related terms ==== ==== Translations ====