[jonathonadler]

Can anyone please explain why electricity is called hydro?

[jszymborski]

Because a large amount of Ontario/Quebec electricity came from hydroelectric sources, and because the energy utility company in Ontario is Hydro One and in Quebec Hydro Quebec, "hydro" has sorta become synonymous.

[PDoyle]

Google can:

https://www.google.ca/search?q=why%20is%20electricity%20call...

[brianwawok]

If a waterway is used to make it i.e. a dam.