i Register
In some senses, to is marked as informal, UK, US, colloquial. Watch for register when choosing this word.
particle
A particle used for marking the following verb as an infinitive.
I want to leave.
He asked me what to do.
As above, with the verb implied.
"Did you visit the museum?" "I wanted to, but it was closed."
If he hasn't read it yet, he ought to.
Used to indicate an obligation on the part of, or a directive given to, the subject.
You are to go to the store and buy a bottle of milk.
conj
In order to.
I went to the shops to buy some bread.
prep
In the direction of; towards.
She looked to the heavens.
Indicating destination or final position: In the direction of, so as to arrive at or reach.
We are walking to the shop.
The water came right to the top of this wall.
Used to indicate the target or recipient of an action.
I gave the book to him.
I spoke to him earlier.
So as to contact, press against, impact, etc.
I fixed the notice to the wall.
Put your shoulder to the door.
So as to become or reach: indicating a terminal state resulting from an action.
His face was beaten to a pulp.
I sang my baby to sleep.