Related topics: Weapons
an empty space on a piece of paper, where you are supposed to write a word or letter:
When you've filled in the blanks, hand the form back to me.
used to say that you cannot remember something:
I'm trying to think of his name, but my mind's a complete blank.
a cartridge (=container for a bullet in a gun) that contains an explosive but no bullet:
Soldiers fired blanks into the crowd.