Believe:

[athoughtfulman]

If something is untrue, is it a belief? Even though we 'believe' it is true?

If something isn't true, then I would hold that it is non-belief, not a negative belief.

Can you explain please teacher. Because you stated:

belief - any cognitive content held as true
source: http://wordnetweb.princeton.edu/perl/webwn?s=belief

If we take the above definition as true, then every single thing that we understand and recognize as true, is counted as a belief. So everyone is a believer in something, but being a believer does not mean you have faith.

Or is this just your opinion. Who is to say your opinion is correct?

It's not an opinion, I am quoting the dictionary. Read the definition - belief - any cognitive content held as true. If you want to dispute the truth of the dictionary, take it up with them. I am merely using it because you asked.

And the definition of cognitive content is - the sum or range of what has been perceived, discovered, or learned

If we accept the above definitions, then anything that has been perceived, discovered, or learned is a belief, which means that anything we hold as true is a belief. As for what is not true, the correct way to describe it would be non-belief.