The Buffalo plant is aiming for a gigawatt of annual cell production by 2019:

https://www.bloomberg.com/news/articles/2017-08-31/tesla-sta...

Which is admittedly not large by global standards, but bigger than any solar manufacturing facility that has operated in the US.

> The name Gigafactory comes from the word “Giga,” the unit of measurement representing “billions.” The factory’s planned annual battery production capacity is 35 gigawatt-hours (GWh), with one GWh being the equivalent of generating (or consuming) 1 billion watts for one hour. This is nearly as much as the entire world’s current battery production combined.

via https://www.tesla.com/gigafactory

Doesn't explain why they call Buffalo's operation a "Gigafactory," but that's the origin of the name for the more well-known Nevada-based Gigafactory.

Because it's really smart branding. Giga as a prefix has come to mean "really big, bigger than mega" colloquially, not just the metric uses of it.

Maybe it's just a form of inflation of hype :) What used to be called mega this and mega that, is now called giga this and that?

If you put "giga" everywhere you increase the hype, increased hype probably means a higher share price, a higher share price means more money for investors (virtual or real money, it doesn't matter), more money is good.

Excellent point, this is merely a megafactory.

(A billion square ft factory, according to Wolfram Alpha, would occupy ~35 square miles or 92 sq. km.)

it's version 2, the density of components increased