It’s a 7 letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove 4 letters from it, it remains the same.
If we remove 5 letters from it, it remains the same.
If we remove 6 letters from it, it remains the same.
If we remove all letters from it, it remains the same.
What is it?
Answer
Postbox or mailbox. No matter how many letters are removed from it, it remains the same.