To. Vs of

  • I am looking for the key of my room.

  • I am looking for the key to my room.

I have just known that the second is right and the first is wrong. However, sometimes it is confusing in a lot of situations to discern what the right one is.

Is there any rule in regard to the usage of to and of, particularly when we want to describe the belongings or possessions of something?!

Do I have to say

  • the damage to my house, or the damage of my house

  • the door to my room, or the door of my room

  • the password to my account, or the password of my account?

  • The most natural phrases (to my British English ears) are "I am looking for the key for my room", and "the password for my account". Jan 16, 2019 at 10:00

2 Answers 2


I have studied four Indo-European languages in addition to my native English. If there are any rules on which prepositions are proper in which situations, they are not easily discerned or explicated in any of those languages. In English, the predominant preposition relating to accessibility seems to be "to."

So "door to that room," "key to that lock," and "password to that account" are all idiomatic. However, "door of that room," "key for that lock," and "password for that account" are also idiomatic.

That quasi-rule about "to" being associated with accessibility has no apparent relevance to the phrase "damage to," but "to" is idiomatic although sometimes "damage in" will be idiomatic.

EDIT: Although "the key of that lock" does not sound euphonius, "that lock's key" sounds perfectly natural. Prepositions are weird.

  • 1
    "the key of that lock" is euphonious enough if the emphasis is on that, as compared with "the key of this lock". But it does seem to need emphasis on one of the words "key", "that" or "lock" - it doesn't sound right as a "neutral" reference to the object in question.
    – alephzero
    Jan 15, 2019 at 18:02
  • @alephzero Agreed. It is like many things in English: exceptions abound. But the primary points that I wanted to make were that: (a) "to" is idiomatic in all the examples given, (b) sometimes more than one preposition will work, and (c) usage of prepositions is not subject to clear-cut rules. Jan 15, 2019 at 18:18
  • 2
    I wouldn't consider "door of that room" to be idiomatic. Jan 15, 2019 at 20:27
  • 2
    "The door of the room suddenly blew open" is not idiomatic? Jan 15, 2019 at 21:06
  • +1 for a most intelligent answer, defying those who seek rules for everything as did Professor Grammar on the BBC World Service years ago.
    – JeremyC
    Jan 15, 2019 at 23:06

The choice of to or of is largely governed by idiom and will vary according to the context. More often than not, native English speakers will refer to the key to the safe, the door, the house, resolving a problem and much else.

It's idiomatic. In fact, in most cases, they will simply say the room/safe/door key but that's not what you are asking about.

The key of my room is acceptable but less likely than the key to my room. And the same is true for the door and the password. Damage is definitely to something and NOT of something.

Google Books Ngram Viewer indicates that while the expression the key of was twice as popular as the key to in the first half of the 19th century, the key to subsequently prevailed and is now about six times as common as the key of.

It's hard to make a rule but as a guide, prefer the key to as the safer option in most instances.


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