When you take me out of a window you leave a grieving wife. When you stick me in a door you will save somebody’s life. What am I?

Riddle: When you take me out of a window you leave a grieving wife. When you stick me in a door you will save somebody's life. What am I?

Riddle: When you take me out of a window you leave a grieving wife. When you stick me in a door you will save somebody’s life. What am I?

Show answer

The letter ‘n’. Take it from the word ‘window’ and you are left with ‘widow’. Add it to the word ‘door’ and you get ‘donor’.