gigadeath 

The cataclysmic death of a billion people or more. This is equivalent to one thousand megadeaths. This does not need to occur in a single event, but from a connected cause. This word was derived from "megadeath", which was coined in 1953 to describe the results of nuclear war. In contrast, "gigadeath" was coined to describe the more massive catastrophe of industrial civilization combined with peak oil, global warming, ecological degradation, and explosive population growth overshooting the global carrying capacity.

"Abrupt climate change would inevitably lead to gigadeath."

"Humans can live sustainably on this planet, but only after a few gigadeaths."

gigadeath by Gigady Death February 16, 2010

Gigadead 

Gigadead is a classically-based Speed Metal or Death Metal band from Minnesota, USA. They formed around the year 1990. The main writer is associated with a Kublai Khan member (they had an ex Megadeth guitarist). These same musicians (Idso, River and Pelton) also have ties with the main writer from Kronk and Realm (Milwaukee, Wis). Unlike Bay Area California bands though, Gigadead's style has always seemed more closely related to Scandinavian Death Metal or Germanic Speed Metal.

Google "Gigadead"

Gigadead by Gigadead February 11, 2013

gigantathon

Used to describe something so large that it’s bigger than big and bigger than gigantic.

Girl asks her BF...”Is Broderick’s cock big?”
Friend responds “Girl, it is gigantathon”

gigantathon by broders999 September 3, 2019

gigabeat

a great mp3/wma/wav player by Toshiba. it beats the shitty iPod by a longshot. it boasts a larger screen, that ROTATES, like PivotPro on PC if you know what that is, it holds higher bitrates for higher quality than just the shitty 128kbps mp3 and mp4 codec iPod uses through the gay iTunes. the software toshiba includes is decent. i recommend it to anyone who hates the click wheel, like me, and for people that desire something sexy and different. amen

-dude, i just bought my gigabeat today! it rapes the ipod up the ass!
-sweet yo!

gigabeat by ipodhater02 July 24, 2008