What's a 'tank'?

[Hamish]

Here it is known as a storage device for rainwater. Elsewhere known as a heavily armoured vehicle with a big gun in front.

I am not personally fond of it's use in relation to kilts, but there you go!

I am right with you on that one, Graham.

Maybe I am unusual (NO comments, if you please!) but I have one in, of all places, my car. Instead of rainwater this one contains something called 'petrol'. ;)

[tomcherv]

And don't leave the SCUBA divers out of this. Most people refer to the devices containing compressed air as tanks.

The organization that taught me (and for whom I later taught), however, refered to them as cylinders.