How do i hide a whole worksheet?

i've tried to click on that particular worksheet in a workbook and
hide just it, however it hides the whole workbook. i have a workbook
where people need to see the first 2 worksheets. However the 3rd
worksheet is a database of information that is connected to the first
2 worksheets so it needs to (and i would like it to) stay with the
whole workbook but just hidden so no one messes with it.

is this posisble?