The question often comes up whether it is better to use a dash "-" or an underline "_" in websites, in page names.
Is it better to name a page
toner-cartridge.html
or
toner_cartridge.html
There is a simple answer to this. Google will tend to consider it a single term if connected by an underscore, and will tend to consider it as two separate words if you use a dash.
Otherwise, Google is perfectly happy with either one.