0 a small square on a paper form where you can put a tick to show that you want something or that something is correct or has been dealt with:
They believed that there should be a citizenship check box on the voter-registration form.
There is a checkbox to opt out of third-party mailings.
I logged on to a dating website and clicked the check boxes for the kind of women I'd be interested in dating.
The Save Password checkbox is grayed out so I can't check it.