Riddle

What is neither inside the house nor outside the house but a necessity for any home?

Choose an answer

A.Doors
B.Curtains
C.A porch
D.Windows
Hint: It's a word with 7 letters, starting with "W".

Answer

Windows

Why this is the answer

Windows are set into the wall of a house -- not purely inside or outside -- yet every home needs them for light and ventilation.

This riddle is filed under Hard/Difficult Riddles and rated Medium.