where

where is on the Basic English 850 List.

when - where - while

where is one of the 1000 most common headwords.

when - where - whether

Preposition

(In or to) what place or situation.
Where do you live?

Where did the man go?

I wonder where they will take us to.
(relative) (In or to) the place or situation in which.
The room where the people cook the food is not cold.

Where I'm from, we don't eat much fish.

I'll go where you go.

Where people were concerned, his threshold of boredom was low.

This is where I live.

That's where you are wrong.

Stand over here where the light is good.

Sit where I can see you.

You'll be right here where you belong.
You use where to introduce a clause that contrasts with the other parts of the sentence.
Where Nixon was secretive and suspicious, Ford was relaxed, open and candid.