to

Từ điển Oxford Advanced Learner 8th

to preposition, infinitive marker, adverb before consonants [tə] before consonants NAmE [tə] before vowels [tu] before vowels NAmE [tu] BrE strong form [tuː] AmE strong form [tuː]
preposition  For the special uses of to in phrasal verbs, look at the entries for the verbs. For example see to sth is in the phrasal verb section at see.
1. in the direction of sth; towards sth
• I walked to the office.
• It fell to the ground.
•It was on the way to the station.
•He's going to Paris.
•my first visit to Africa
•He pointed to something on the opposite bank.
•Her childhood was spent travelling from place to place.
2. ~ the sth (of sth) located in the direction mentioned from sth
• Place the cursor to the left of the first word.
• There are mountains to the north.
3. as far as sth
• The meadows lead down to the river.
• Her hair fell to her waist.
4. reaching a particular state
• The vegetables were cooked to perfection.
• He tore the letter to pieces.
•She sang the baby to sleep.
•The letter reduced her to tears (= made her cry).
•His expression changed from amazement to joy.
5. used to show the end or limit of a range or period of time
•a drop in profits from $105 million to around $75 million
• I'd say he was 25 to 30 years old (= approximately 25 or 30 years old).
• I like all kinds of music from opera to reggae.
•We only work from Monday to Friday.
•I watched the programme from beginning to end.
6. before the start of sth
• How long is it to lunch?
• (especially BrE) It's five to ten (= five minutes before ten o'clock).
7. used to show the person or thing that receives sth
• He gave it to his sister.
• I'll explain to you where everything goes.
•I am deeply grateful to my parents.
•Who did she address the letter to?
• (formal)To whom did she address the letter?
8. used to show the person or thing that is affected by an action
• She is devoted to her family.
• What have you done to your hair?
9. used to show that two things are attached or connected
• Attach this rope to the front of the car.
10. used to show a relationship between one person or thing and another
• She's married to an Italian.
•the Japanese ambassador to France
•the key to the door
•the solution to this problem
11. directed towards; concerning
• It was a threat to world peace.
• She made a reference to her recent book.
12. used to introduce the second part of a comparison or ↑ratio
• I prefer walking to climbing.
• The industry today is nothing to what it once was.
•We won by six goals to three.
13. used to show a quantity or rate
• There are 2.54 centimetres to an inch.
• This car does 30 miles to the gallon.
compare ↑per
14. in honour of sb/sth
•a monument to the soldiers who died in the war
• Let's drink to Julia and her new job.
15. while sth else is happening or being done
• He left the stage to prolonged applause.
16. used after verbs of movement to mean ‘with the intention of giving sth’
•People rushed to her rescue and picked her up.
17. used to show sb's attitude or reaction to sth
• His music isn't really to my taste.
• To her astonishment, he smiled.
18. used to show what sb's opinion or feeling about sth is
• It sounded like crying to me.

Word Origin:
Old English tō (adverb and preposition), of West Germanic origin; related to Dutch toe and German zu.
Idiom: ↑and fro
 
infinitive marker  To is often used before the base form of a verb to show that the verb is in the infinitive. The infinitive is used after many verbs and also after many nouns and adjectives.
1. used to show purpose or intention
• I set out to buy food.
• I am going to tell you a story.
•She was determined to do well.
•His aim was to become president.
•To be honest with you, I don't remember what he said.
2. used to show the result of sth
• She managed to escape.
• It was too hot to go out.
•He couldn't get close enough to see.
3. used to show the cause of sth
• I'm sorry to hear that.
4. used to show an action that you want or are advised to do
• I'd love to go to France this summer.
• The leaflet explains how to apply for a place.
•I don't know what to say.  To can also be used without a following verb when the missing verb is easy to understand
•He asked her to come but she said she didn't want to.
5. used to show sth that is known or reported about a particular person or thing
• The house was said to be haunted.
6. used to show that one action immediately follows another
• I reached the station only to find that my train had already left.
7. am, is, are, was, were ~ used to show that you must or should do sth
• You are not to talk during the exam.
• She was to be here at 8.30 but she didn't arrive.

Word Origin:
Old English tō (adverb and preposition), of West Germanic origin; related to Dutch toe and German zu.
 
adverb (usually of a door)
in or into a closed position
• Push the door to.
see also ↑toing  For the special uses of to in phrasal verbs, look at the entries for the verbs. For example set to is in the phrasal verb section at set.

Word Origin:
[to] Old English tō (adverb and preposition), of West Germanic origin; related to Dutch toe and German zu.